Showing papers in "Environmental Technology and Innovation in 2021"

Protocols for synthesis of nanomaterials, polymers, and green materials as adsorbents for water treatment technologies

Abstract: Water pollution caused by numerous pollutants has become one of the critical problems globally. Different technologies and materials are used for the treatment of wastewater. There is a need for protocols and procedures that act as guidelines for researchers to develop and evaluate new adsorbent materials for wastewater treatment. This review takes a step toward developing organized protocols and procedures for the synthesis of nanomaterials, polymers, and green materials as adsorbents used for water purification. In the present review, protocols, and procedures for the synthesis of adsorbents, such as nanomaterials, waste-derived materials, and polymers are proposed Furthermore, protocols for evaluating these materials for water treatment are provided. The reported protocols and procedures will provide guidelines for researchers and industrial workers to develop and evaluate new materials for water treatment.

Heavy metal water pollution: A fresh look about hazards, novel and conventional remediation methods

Abstract: Water pollution is one of the global challenges that society must address in the 21st century aiming to improve water quality and reduce human and ecosystem health impacts. Industrialization, climate change, and expansion of urban areas produce a variety of water pollutants. In this work, we discuss some of the most recent and relevant findings related to the release of heavy metals, the possible risks for the environment and human health, the materials and technologies available for their removal. Anthropogenic activities are identified as the main source of the increasing amounts of heavy metals found in aquatic environments. Some of the health hazards derived from repeated exposure to traces of heavy metals, including lead, cadmium, mercury, and arsenic, are outlined. We also give some perspectives about several techniques used to detect heavy metals, as well as about the factors that could affect the contaminant removal. The advantages and drawbacks of conventional and non-conventional heavy metal removal methods are critically discussed, given particular attention to those related to adsorption, nanostructured materials and plant-mediated remediation. Some of the commercial products currently used to eliminate heavy metals from water are also listed. Finally, we point out some the requirements and opportunities linked to developing efficient methods for heavy metal removal, such as the ones that exploit nanotechnologies.

Modern trend of anodes in microbial fuel cells (MFCs): An overview

Abstract: Microbial fuel cells (MFCs) is highly efficient bioelectrochemical systems in which bacteria are utilized to oxidize the organic substrate and produce electricity. The main component of an MFCs is the anode, in which bacterial attachment is promoted and the generation and transfer of electrons occurs. Therefore, the interest of introducing novel and innovative anode materials for attaining a high performance of MFCs is a concern that is growing in the modern era. In this review article, different conventional and modern anode materials are briefly discussed considering their advantages and limitations. Among all, the natural biomass-derived materials were found as one of the best sources to meet the present challenges to utilize them as anodes in MFCs. The natural derived anodes presented some limitations which can be addressed through metal oxide composites as described in this article. The oxidation mechanism of pollutants on the surface of anode along with their bacterial interactions are also briefly summarized. This review is limited to the performance and development of the anode in MFCs.

A review of constructed wetland on type, treatment and technology of wastewater

Abstract: The performance of constructed wetland depends upon the types of constructed wetland, vegetation, applied hydraulic load, and media used in the bed. This paper describes the review of constructed wetland on type, technology and treatment of various types of wastewater generated such as textile waste, dairy waste, industrial waste, piggery waste, tannery waste, petrochemical waste, municipal waste, etc. The review summarizes the types of constructed wetlands considering media, vegetation, removal efficiency, construction cost, maintenance cost and land area requirement using life cycle cost analysis. The review compares how and why constructed wetland is a better option as per treatment efficiency, their payback period and cost-effective with the other wastewater treatment technologies. Further, there is no proper guidelines for the selection of media and vegetation in the constructed wetland. It is found that Typha Latifolia and Phragmites Australis have a better removal efficiency than other species. Lightweight Expanded Clay Aggregate (LECA), saw dust, zero-valent iron and gravels can be effectively used as a media for the removal of organic matter, phosphorus, sulphate and arsenate. Constructed wetland with low Hydraulic Loading Rate (HLR) performs exceptionally well and can remove 80%–91% Biochemical Oxygen Demand (BOD), 60%–85% Chemical Oxygen Demand (COD) and 80%–95% Total Suspended Solids (TSS). It requires a very low operation and maintenance than others. This review on constructed wetland further suggests research and development related to land area, media, plants, engineering design and automation of treatment units.

A review on the waste biomass derived catalysts for biodiesel production

Abstract: Biodiesel is produced through the process of transesterification of different edible and non-edible oils and animal fats. The process takes place either in the presence of a homogeneous or heterogeneous catalyst. A suitable catalyst is selected based on the amount of free fatty acid (FFA) content present in the oil. The major difference between homogeneous and heterogeneous catalysts is that the homogeneous catalysts are insensitive to the amount of free fatty acids present in the oil. Also, homogeneous catalysts are toxic, highly flammable, and corrosive. Besides, the use of homogeneous catalysts produces soaps as a by-product and a bulk of wastewater which requires additional pretreatment methods and expenses for proper disposal. The research on the biodiesel synthesis in the presence of heterogeneous catalysts (carbon-based catalysts) is continuously studied to achieve a suitable process to produce biodiesel and to improve fuel quality on an industrial scale. Heterogeneous catalysts have great significance in the biodiesel production because of their simple and less expensive manufacturing process, ease of separation, and high reusability. They can be prepared easily by functionalizing the carbon surface with acid or base. Carbon-based catalysts have a high surface area and porosity that can enhance the rate of the esterification/transesterification process. Also, solid acid catalysts can convert the low-quality feedstocks to biodiesel in the presence of active acidic sites. Besides, carbon-based catalysts can be produced through waste e.g. sugarcane bagasse and their use make the production of biodiesel “Greener” one. This review paper is mainly based on the utilization of different catalysts derived from waste biomass in the biodiesel. Under optimum conditions biodiesel (FAME) yields 90%–99% were reported in the literature.

Removal of emerging micropollutants originating from pharmaceuticals and personal care products (PPCPs) in water and wastewater by advanced oxidation processes: A review

Abstract: Because of their intrinsic potential to produce metabolic effects on the human body at smaller concentrations, pharmaceuticals and personal care products (PPCPs) are a distinct category of emerging environmental pollutants. Due to their widespread intake, limited metabolic capacity, and indecorous disposal, PPCPs pollutants are commonly found in water supplies and wastewater treatment plants. If partly oxidized PPCPs are introduced into wastewater treatment plants, they will disrupt biological wastewater treatment procedures. As a result, traditional wastewater treatment plants are inadequate for PPCPs elimination. PPCPs have been effectively eliminated using advanced oxidation methods such as electrochemical oxidation, ultrasonication, and ionizing radiation. This review summarizes recent studies on the removal of PPCPs by advanced oxidation processes, as well as knowledge useful for applying these processes in water and wastewater treatment. The degradation of different classes of PPCPs has been reviewed to analyze (i) significant factors — initial concentration of PPCPs, ultrasonication power, radiation dose, current density, temperature, pH, time, and effect of catalysts; (ii) degradation efficiency of the processes when applied in combination with other advanced oxidation methods; (iii) key factors that affect the removal of PPCPs based on their properties. In addition, suggestions for future studies on advanced oxidation methods and their limitations were discussed. Overall, this review could aid in providing an in-depth understanding of the current research trends concerning PPCPs and advanced oxidation processes.

Facile synthesis of zinc oxide nanoparticles loaded activated carbon as an eco-friendly adsorbent for ultra-removal of malachite green from water

Abstract: Green synthesis ultrasonic method is reported for the preparation of zinc oxide nanoparticles loaded on activated carbon (AC) derived from coffee waste. The zinc modified AC was used effectively for the elimination of malachite green (MG) from wastewater. The examined batch adsorption parameters are; initial pH (2–9), adsorbent dose (0.10–0.50 g/100 mL), mixing time (5–120 min), MG concentrations (25–300 mg/L) and temperature (298–318 K). XRD, SEM/EDS, FT-IR and TGA/DTA techniques were used to characterize the developed Zn(OH)2-AC composite. The results demonstrated that the adsorption capacity of Zn(OH)2-AC composite was improved with incremental of the initial dye concentration, pH, and temperature, and decreased as the Zn(OH)2-AC composite dose was increased. The Langmuir isotherm model ( R 2 = 0 .97) showed better conventionality than the Freundlich model ( R 2 = 0 .80) with a maximum removal capacity of 303.03 mg/g at 318 K and pH 7.0. The kinetic results revealed that the equilibrium data well follow the pseudo-second-order model. The thermodynamic investigations indicated the spontaneous and endothermic removal of MG. The cycling test exhibited that the developed Zn(OH)2-AC composite had virtuous repeatable adsorption/desorption performance particularly until the fourth cycle. In addition to comparatively shorter adsorption time, relatively high adsorption capacity, reasonable reuse performance, and being of cost-effective and eco-friendly of the developed Zn(OH)2-AC composite make it economic, effective and hopeful adsorbent for cleaning MG containing wastewaters.

A green approach for the synthesis of silver nanoparticles by Chlorella vulgaris and its application in photocatalytic dye degradation activity

Abstract: Biosynthesis of the silver nanoparticle (AgNPs) is gaining significant importance since it is eco-friendly and can withstand variable environmental conditions. In this present study, AgNPs have been synthesized by using a freshwater green alga, Chlorella vulgaris. For the improved production, experiments on the standardization of AgNPs synthesis were investigated at different parameters. The results affirmed that the synthesize of AgNPs was at 8:2 v/v in extract ratio, pH 12 in the solution of AgNO3, 3 mM in molarity of AgNO3, shaking process in the incubation of reactants and 24 h time in synthesis period. Further, synthesized AgNPs were characterized by using spectroscopic and microscopic techniques. The synthesized AgNPs showed the Surface Plasmon Resonance (SPR) peak between the 410–450 nm. Fourier Transform Infrared Spectroscopy (FTIR) revealed that the algal extract has stabilized with the nanoparticles by capping. The Field Emission Scanning Electron Microscopy (FESEM) analysis confirms the spherical shape of the AgNPs with an average size of 55.06 ± 9.67 nm. The X-ray diffraction (XRD) analysis showed a crystalline nature of the particle with an average size of 61.89 ± 12.13 nm. The photocatalytic decolorization of the methylene blue by using synthesized AgNPs was evaluated under the sunlight irradiation method. The synthesized AgNPs have shown 96.51% of photocatalytic decolorization activity by using methylene blue dye (100 ppm) within 3 h incubation time.

Mapping the research trends on blockchain technology in food and agriculture industry: A bibliometric analysis

Abstract: Blockchain is an undeniably ingenious leading technology that has attracted the attention of academics and practitioners in different industries and disciplines. Due to the increasing interest of academic scholars in agri-food supply chain, this research aims to examine blockchain technology with a focus on the food and agriculture studies. Therefore, a bibliometric technique was adopted to detect the prominent trends and themes in this domain through analysing the substantial articles, authors, countries, and keywords. This research attempts to expand a graphical mapping of the bibliographic information of food and agriculture research using the R package bibliometrix and Visualisation of Similarities (VOS) viewer application. Thus, the present research performed the following analyses: the co-occurrence of author keywords, multiple correspondence analysis, bibliographic coupling analysis, co-citation analysis, and network view map analysis. The findings of the network view map revealed that food and agriculture studies have been categorised into three clusters, and the terms mostly used in the title and abstract of the articles were traceability, transaction, Internet of Things (IoT), safety, and food supply chain.

Modeling of CO2 capture ability of [Bmim][BF4] ionic liquid using connectionist smart paradigms

Abstract: The burning of fossil fuels produces large amounts of exhaust gases containing carbon dioxide (CO2). The emission of CO2 into the atmosphere is widely known as the leading cause of global warming and climate change. The separation processes are responsible for capturing the CO2 to reduce its undesirable effects on the environment. Since the conventional processes have their drawbacks, it is crucial to find a more environment-friendly process for CO2 capture. Recently, ionic liquids (ILs) have become an interesting candidate for CO2 capture. In this study, the solubility of CO2 in the 1-n-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) is estimated using six different artificial intelligence (AI) techniques, including four artificial neural networks (ANN), support vector machines (LS-SVM), adaptive neuro-fuzzy interface system (ANFIS). The cascade feed-forward neural network has been found as the best model for the considered matter. This model predicts overall experimental datasets with excellent accuracy of AARD = 6.88%, MSE = 8 × 1 0 − 4 , and R 2 = 0 . 98808 . The maximum mole fraction of CO2 in the ionic liquid (i.e., 0.8) can be obtained at the highest pressure and the lowest temperature.

Removal of organic pollutants from water by Fe2O3/TiO2 based photocatalytic degradation: A review

Abstract: The occurrence of persistent organic pollutants (POPs), such as dyes, pharmaceuticals and endocrine disrupting compounds in the aquatic environment is attracting significant concerns worldwide due to their bioaccumulation, toxicity, and potential risk to the environment. These contaminants are produced daily in large amounts and released onto water bodies intentionally or accidently. Conventional wastewater treatment plants are inefficient for the degradation of these pollutants. Thence, the development of sustainable and effective techniques for the removal of POPs is essential. In this sense, the application of photocatalysis for the removal of POPs is a promising, effective and sustainable technology. TiO2 is the most common studied photocatalyst due to its low-cost, availability and non-toxicity. However, TiO2 exhibits a high band gap around 3.2 eV, which restricts its use under visible light. In this regard, attempts have been investigated to shift the adsorption of TiO2 to visible light by reducing its band gap energy to below 3.2 eV. Doped photocatalyst is a successful approach to reduce the band gap energy of TiO2. Fe2O3 is considered an ideal dopant due to its unique properties such as magnetic properties and low bandgap. Fe2O3-TiO2 has shown remarkable performance for the removal of POPs as well as successful recovery and reusability of the photocatalyst after the treatment process. This review attends at providing deep insights on the synthesis methods of Fe2O3-TiO2, particularly, the sol–gel method. The photoactivity of Fe2O3-TiO2 towards POPs is also presented along with the parameters that influence the photodegradation process. Future research needs are also addressed.

Current technologies for recovery of metals from industrial wastes: An overview

Abstract: Fast industrialization has increased the demand for heavy metals, on the other hand, high-grade ore natural reserves are belittling. Therefore, alternative sources of heavy metals need to be investigated. Massive amounts of industrial wastes are being generated annually. The majority is sent to landfills or to incinerators, which eventually poses environmental challenges such as ecological contamination and health hazards to living beings. Such industrial wastes contain hazardous elements of various metals (Au, Ag, Ni, Mo, Co, Cu, Zn, and Cr), whose improper disposal leads to adverse effects to human being and the environment. As a result, methods for industrial waste management such as reuse, remanufacturing, and recycling have received much attention due to the fact that they improve cost effectiveness over time and enable the metal recovery businesses to thrive profitably. The present study provides a state of art review on the current technologies existing for the recovery of precious metals from industrial wastes streams to analyse the sustainability. Among the wastes, spent petroleum catalysts, medical waste, electronic scraps, battery wastes, metal finishing industry waste, and fly ash are some of the largest industrially-generated wastes. Various metal recovery processes involve physical, chemical, and thermal characteristics of waste streams and target metals for separation and extraction. The current challenges of pyrometallurgy, modification on the hydrometallurgy, physical and chemical methods and other advanced technologies are presented in this review. The hydrometallurgical method, which involves dissolving and leaching, is a proven and successful process for recovering metals from various raw materials. Several other recovery methods have been proposed and are currently being implemented; the problem is that most of them are only successful in retrieving certain metals based on specific properties of industrial waste. The recovered metal solutions are further concentrated and purified using adsorption, cementation, chemical precipitation, ion exchange, membrane filtration and ion flotation techniques, which can also be applied to other liquid waste streams. The recovery method only makes sense if the recovery cost is much less than the value of the precious metal. The limitations placed on waste disposal and stringent environmental legislation require environmental-friendly metal recovery technologies. This review paper provides critical information that enables researchers to identify a proper method for metal recovery from different industrial wastes, and also it benefits researchers and stakeholders in determining research directions and making waste management-related decisions.

Recent advances and applications of municipal solid wastes bottom and fly ashes: Insights into sustainable management and conservation of resources

Abstract: Waste destruction through incineration has widely become an acceptable and popular choice globally. Despite being regarded as a sustainable option, if not operated and managed properly, it can be one of the least environmentally preferred options. It is agreed that the waste from municipal solid waste (MSW) can be considered a renewable energy resource due to its potential of being converted from “waste” into useful products and energy. This review for the first time incorporates both municipal solid waste bottom ash (MSW-BA) and municipal solid waste fly ash (MSW-FA); and discusses their physicochemical characterizations, leaching mechanisms, and pre-treatment methods. Additionally, it incorporates, discusses, and critically reviews the recent advances and applications of MSW-BA and MSW-FA, and explore the potential of utilizing ashes as a sustainable option by conserving natural resources.

Smart Home Energy Management Systems in Internet of Things networks for green cities demands and services

Abstract: Today, 44% of global energy has been derived from fossil fuel, which currently poses a threat to inhabitants and well-being of the environment. In a recent investigation of the global demand for energy consumption across various energy consumption sectors, the building sector has been shown to be one of the primary energy consumers, with a high percentage of energy consumption deemed as unnecessary. This as a result of poor management practice and implementation of strategies to avoid excess energy consumption. Over the years, researchers in both academia and industries have focused on various techniques to deal with unnecessary energy consumption and ensuring a healthy living environment for green smart cities. Among these techniques is Smart Home Energy Management Systems (SHEMs), which transform electric home appliances, sensor nodes, into autonomous devices in order to manage energy consumption effectively. This study presents an analysis of smart home energy management system with the goal to identify current trends and challenges for future improvement. The result reveals lack of quality attributes such as security, privacy, scalability, interoperability, and difficulty in managing and adapt to the thermal comfort satisfaction of residents, exposing them to health risks. Lastly, the study described opportunities for future research that ensure energy-efficient smart homes free of unnecessary energy consumption, health challenges, and cyber security attacks.

Spatial effect of innovation efficiency on ecological footprint: City-level empirical evidence from China

Abstract: Improving the level of innovation is a driving force for the sustainable development of urban economy, ecology and society. Improved data envelopment analysis (DEA) is used herein to investigate 280 cities in China and measure their innovation efficiency during 2012–2018, and a spatial measurement model is applied to analyse the impact of innovation efficiency on ecological footprint. In addition, this paper further discusses the impact of innovation efficiency on ecological footprint of different regions, comparing innovative and non-innovative cities, and eastern, central and western cities. The major findings are as follows: (1) A significant positive spatial relationship exists in the ecological footprint of Chinese cities as a whole, including eastern and central cities. (2) Promoting innovation efficiency significantly inhibits the ecological footprint of not only local region, but also neighbouring regions, with coefficients of −0.2488 and −0.1638 respectively. (3) The inhibitory effect of the increase in innovation efficiency in innovative cities on ecological footprint is stronger in local and neighbouring regions than non-innovative cities. In eastern and central Chinese cities, local ecological footprint is subject to a potent inhibitory effect from the progress in innovation efficiency, while the improvement in innovation efficiency has shown a significant promoting effect in the western region; and the ecological footprint of neighbouring regions only in the eastern cities is inhibited by the improvement of innovation efficiency of local regions.

Roughness and wettability of biofilm carriers: A systematic review

Abstract: Since the 1980s, many studies have reported the importance of biofilm carrier roughness on microbial attachment. Roughness can enhance the wettability (hydrophobicity or hydrophilicity) of biofilm carriers. Roughness and wettability can lead to firmly attached biofilms with proper thickness communities and can protect them from being detached. However, roughness and wettability have not been adequately defined and discussed with regard to biofilm activity. Also, there is a contradiction among literature reports on how wettability affects bacterial adhesion. This systematic review presents a discussion of these properties as they affect biofilm formation and stability. In addition, it critically reviews past developments that occurred to advance carrier properties. It was found that an effective biomass immobilization requires rough surfaces having edges, and peaks and valleys. These carrier surfaces need to be substantially less or more hydrophobic/hydrophilic than the suspended biomass. The difference in wettability is the driving force to determine the degree of interaction with bacteria. Rough and wetted surfaces ensure the initial adhesion of bacterial communities and provide robust protection from detachment. If roughness was inadequate and the carrier wettability range was close to that of the biomass, it would significantly destabilize the overall biofilm system performance and deteriorate biofilm attachment.

Critical review on microbial community during in-situ bioremediation of heavy metals from industrial wastewater

Abstract: This review aims to summarise recent studies on in-situ microbial remediation of heavy metals from industrial wastewater. The major environmental issue of heavy metal(s) pollution in groundwater is worldwide due to the continuous development of industrial activities. Microbial remediation has been reported to show intense changes in the microbial diversity induced by heavy metals, environmental pollution, and adaptation mechanisms that enable microbes to live in environments contaminated by metals. In-situ bioremediation is reported as a solution for emerging contaminant problems; microbes are beneficial to remediate the contaminated environment. The assessment approaches for evaluating the efficacy of remediation through in-situ bioremediation technology in future research leads to further attention by the researchers. The success of bioremediation depends upon the polluted site, microbial species selection, and availability of toxic metals for uptake. It is a cost-effective microbes-based method for remediation of toxic metals. This review provides novel approaches for evaluating these remediation technologies and integrated measurement methods to evaluate the efficacy of remediation employing microbes. This review also offers valuable information for understanding the fundamental role of microorganisms in the in-situ bioremediation for pollutant(s) removal process.

Applying environmental Kuznets curve framework to assess the nexus of industry, globalization, and CO2 emission

Abstract: Malaysia has continued to increase the explosive growth rate of its industries in recent years. The rise of globalization has driven Malaysia’s economic development at the ecosystem level of pollution. This research study explores the relationship of CO2 emissions, gross domestic product, globalization, industrialization, and trade openness for Malaysia by using annual data for 1971–2016. By applying the ARDL bound testing approach, the estimates infer that CO2 emissions have steadily risen with high economic growth and affirm the U-shaped environmental Kuznets curve (EKC). Globalization’ index and trade openness surge Malaysian CO2 emissions. While industrialization has a statistically significant negative impact on CO2 emissions. The VECM Granger causality infers the unidirectional causality running from economic growth, globalization, industrialization, and trade openness to CO2 emission in the short-run Finally, this study provides some suggestions to Malaysian policymakers for devising carbon emission reduction strategies.

Can bioplastics be treated in conventional anaerobic digesters for food waste treatment

Abstract: The “European Strategy for plastics” approved by the European Union aims at drastically reducing the use of plastic materials derived from fossil resources, especially single use plastic (SUP) As a consequence, the adoption of biodegradable plastics is forced by different national regulations, especially in France and Italy which banned the usage of single use plastics Being classified as biodegradable and compostable, the major part of these materials is often collected with the Organic Fraction of Municipal Solid Wastes (OFMSW), basically due by food waste, and sent to biological treatment plants, namely composting and anaerobic digestion for bioenergy recovery or their combination This study tested the specific methane production and the relative kinetics of the most common single use biodegradable items (carrier bag, cutlery and plates), available on the market It was demonstrated that sugar cane cellulosic pulp materials have good methane production of 390 L CH4 /kg TVS and a kinetic which is consistent with the anaerobic digestion’s residence time typically applied for OFMSW On the contrary, starch-based bioplastic and PLA materials remained almost undegraded after 250 days and showed low specific methane production yields in the range 100–200​ L CH4 /kg TVS The adoption of acidic and basic pretreatments improved the anaerobic digestion performances of starch-based bioplastic and PLA samples Materials made of poly-hydroxy-alkanoates (PHA) showed higher methane production rates, up to 402 L CH4 /kg TVS in short residence times (around 10 days), which make them adequate to be treated together with food waste in anaerobic digestion plants

Elaboration of Fe3O4/ZnO nanocomposite with highly performance photocatalytic activity for degradation methylene blue under visible light irradiation

Abstract: The magnetite/zinc oxide (Fe3O4/ZnO) nanocomposites were synthesized by the solid-state method using different ratios of zinc oxide and iron oxide. The structural, morphological, and optical properties of nanocomposites were analysed by X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), Raman spectroscopy, transmission electron microscope (TEM), UV–Vis diffuse reflectance spectra (UV–Vis/DRS) and Photoluminescence (PL) spectrophotometry. A significant Raman shift which recorded in nanocomposite due to the ZnO component which is strongly incorporated with the magnetic Fe3O4 nanoparticles. Furthermore, Fe3O4/ZnO has a strongly quenching in PL intensity indicating stability between electrons and holes (e − /h + ). The photocatalytic activities of Fe3O4/ZnO nanocomposites were investigated by the degradation of methylene blue in aqueous solution under visible light in different condition of pH, initial concentration and different trapping agents for free radicals (Tert-butyl alcohol (TBA), p-benzoquinone (BQ) and disodium ethylenediaminetetraacetic acid (Na2-EDTA)). The results revealed that the photodegradation efficiency of ZnO compound with presence of magnetite improved from 13.5% to 88.5%. The optical results show enhancement of nanocomposite absorption under the visible region with a high life time between e − /h + at the optimum ratio between Fe3O4/ZnO (MZ4), which can applied to obtain high photocatalytic degradation of methylene blue under visible light. Finally, the catalytic activity has been stabled when such photocatalyst was utilized again for several cycles.

Efficient removal of congo red dye using Fe3O4/NiO nanocomposite: Synthesis and characterization

Abstract: In the present study, the adsorption of congo red (CR) using Fe3O4/NiO magnetic nanocomposites synthesized via a precipitation method was studied. XRD, EDS, FTIR, TEM, BET, and SEM techniques were used to obtain their specifications. The influence of solution pH, adsorbent dosage, time of experiments, initial concentration of CR, and the temperature has been checked. Among the non-linear isotherm models studied, Langmuir with q m = 210 . 78 mg/g at 293 K and R 2 = 0 . 9983 showed the highest agreement with laboratory results compared to Freundlich, Jovanovic, Halsey, and Temkin models. The results also showed the congo red’s adsorption process on Fe3O4/NiO nanocomposite follows the pseudo-second-order kinetic model. Further, temperature and thermodynamic studies’ effect was carried out, and results showed spontaneously and exothermically the adsorption process. Overall, Fe3O4/NiO nanocomposite, due to low equilibrium time and high adsorption capacity, could remove congo red from contaminated water.

CO2/CH4, CO2/N2 and CO2/H2 selectivity performance of PES membranes under high pressure and temperature for biogas upgrading systems

Abstract: Currently, thermal treatments are used extensively to convert millions of tons of biomass and municipal solid waste into energy products. Although biogas represents ∼ 50% of these energy products, usually disposed due to the difficulty to extract CH4 and H2 (main flammable compounds) from their complex composition contaminated by CO2, N2, etc. Recently, Polyethersulfone (PES) membranes have been employed for that purpose as an effective and cheap technology, however, their permeation properties under higher pressure and temperature are still undefined. Within this context, this research aims to study the influence of high temperatures and pressure on CO2/N2, CO2/H2 and CO2/CH4 selectivity performance of PES membranes and their potential applications in biogas upgrading systems. The experiments were started with preparation of the PES membranes using phase inversion methods, then observing their morphology, physical, chemical, thermal, and mechanical behaviors using SEM, XRD, FTIR, TGA, and universal testing machine. Consecutively, the initial gas separation experiments using CO2 gas were conducted to determine the maximum pressure and temperatures that the synthesized PES membranes can withstand without being damaged or thermally degraded. Based on the results of initial experiments, CO2/CH4, CO2/N2, and CO2/CH4 selectivity of the PES membranes was measured up to 60 °C and 6 bar (absolute pressure) using a set-up built especially for that purpose. Also, the effect of separation temperature and pressure on the separation mechanism were studied. The results revealed that the lowest pressure (1 bar) and the highest temperature (60 °C) can help to achieve the maximum selectivity performance for CO2/N2 (0.91), CO2/H2 (1.25), and CO2/CH4 (3.07), with improvement of 9, 20, and 17%, respectively. In addition, permeability of CO2 > N2 > H2 > CH4 increased by 13.2% (CO2), 15.1% (N2), 11% (H2), and 4.6% (CH4) at the same temperature. Based on that, pressure and temperature are considered as key factors that can be used to enhance the gas permeation and to control their pore shape. Also, PES membranes can be classified as a promising emerging technology for biogas upgrading with high selectivity, especially at high separation temperatures and low pressure.

Microalgae in aquatic environs: A sustainable approach for remediation of heavy metals and emerging contaminants

Abstract: Water pollution has grown to be a grave concern in the world. Direct discharge of wastewater poses risks to the aquatic ecosystems by causing eutrophication and degrades their physico-chemical characteristics. Moreover, wastewater is mainly enriched with recalcitrant toxic substances that pose detrimental impacts on the receiving environments. Conventional treatment approaches are mostly applied to remove nuisance pollutants from aquatic systems but are expensive and inefficient. Exploring microalgae has been found to be an efficient and ecofriendly technique for purification of aquatic environs. Furthermore, microalgae can effectively remove N (90–98.4%), P (66%–98%), Pb (75%–100%), Zn (15.6–99.7%), Cr (52.54%–96%), Hg (77%–97%), Cu (45%–98%) and Cd (2–93.06%)from contaminated aquatic systems. Microalgae play a pivotal role in degrading the complex pesticides ( α -endosulfan, lindane, isoproturon and glyphosate) and emerging concerned contaminants (triclosan, bisphenol A, 17 α -ethinylestradiol, tramadol and diclofenac) in elegant manner from disturbed environs. Apart from toxic pollutant removal, microalgae produce biomass, thereby acts as the efficient source of additional products like biofuel, carbohydrates, lipids and proteins which can make phycoremediation more frugal and sustainable.

Synthesis and characterization of magnetic nanoparticles, and their applications in wastewater treatment: A review

Abstract: The sustainable growth of any society is in direct proportion with developing novel methods and technologies for the management of its environmental quality. The use of Magnetic Nanoparticles (MNPs) has emerged as an efficient tool for remediation of wastewater owing to its intrinsic qualities including size, surface effect, quantum effect, etc. These intrinsic properties of MNPs have diversified their application in managing the qualitative stress on water resources. The present review aims to assess the use of MNPs in removing organic and inorganic contaminants from wastewater. Insights into various synthesis methods and their effects on contaminant removal are also presented. It is reported that MNPs provide target specificity and cost-effectiveness as compared to conventional treatment methods. Moreover, the biological synthesis of MNPs is proven to be eco-friendly and aids in sustainable development. Nearly 100% removal of various types of contaminants such as pharmaceuticals and personal care products, dyes, pesticides, heavy metals, etc. can be achieved through MNPs. Some MNPs have shown a magnetic saturation reaching up to 70 emu/g, and recycling up to 5 cycles with >95% removal efficiency. High pollutant removal efficiency (>98%) can also be achieved in a short time (within 5 min) by MNPs. It is noteworthy that, nanosorption along with the redox reactions are the most frequently used and efficient mechanisms of contaminant removal from wastewater samples.

Barriers to the digitalisation and innovation of Australian Smart Real Estate: A managerial perspective on the technology non-adoption

Abstract: The real estate sector brings a fortune to the global economy. But, presently, this sector is regressive and uses traditional methods and approaches. Therefore, it needs a technological transformation and innovation in line with the Industry 4.0 requirements to transform into smart real estate. However, it faces the barriers of disruptive digital technology (DDT) adoption and innovation that need effective management to enable such transformation. These barriers present managerial challenges that affect DDT adoption and innovation in smart real estate. The current study assesses these DDTs adoption and innovation barriers facing the Australian real estate sector from a managerial perspective. Based on a comprehensive review of 72 systematically retrieved and shortlisted articles, we identify 21 key barriers to digitalisation and innovation. The barriers are grouped into the technology-organisation-external environment (TOE) categories using a Fault tree. Data is collected from 102 real estate and property managers to rate and rank the identified barriers. The results show that most of the respondents are aware of the DDTs and reported AI (22.5% of respondents), big data (12.75%) and VR (12.75%) as the most critical technologies not adopted so far due to costs, organisation policies, awareness, reluctance, user demand, tech integration, government support and funding. Overall, the highest barrier (risk) scores are observed for high costs of software and hardware (T1), high complexity of the selected technology dissemination system (T2) and lack of government incentives, R&D support, policies, regulations and standards (E1). Among the TOE categories, as evident from the fault tree analysis, the highest percentage of failure to adopt the DDT is attributed to E1 in the environmental group. For the technological group, the highest failure reason is attributed to T2. And for the organisational group, the barrier with the highest failure chances for DDT adoption is the lack of organisational willingness to invest in digital marketing (O4). These barriers must be addressed to pave the way for DDT adoption and innovation in the Australian real estate sector and move towards smart real estate.

Environment friendly degradation and detoxification of Congo red dye and textile industry wastewater by a newly isolated Bacillus cohnni (RKS9)

Abstract: Textile industry wastewater (TIWW) is a major source of environmental pollution causing serious threats to all life forms and thus, it must be adequately treated before its final discharge for the safety of environment and public health. In the present study, a potential bacterial strain (RKS9) was isolated from textile (wastewater & sludge) sample for the effective treatment of TIWW resulting in a significant reduction in pollution parameters such as ADMI color (93.87%), COD (77.35%), BOD (86.02%), TDS (66.75%), TOC (67.25%), TSS (60.34%), and phenol (68.55%) within 48 h. This bacterium also decolorized 99% of Congo red dye (100 mg L−1) within 12 h and removed 59.76%, 40.51%, 52.71% and 26.51% cadmium, chromium, lead and nickel, respectively from the TIWW. The activities of azoreductase, laccase, lignin peroxidase (LiP) and manganese peroxidase (MnP) was monitored and metabolites produced during the treatment of dye and TIWW were also analyzed by FT-IR and GC–MS. The phytotoxicity of the untreated and treated TIWW was assessed by seed germination and seedling growth parameters of Phaseolus mungo L. and results showed a significant reduction in the toxicity of the treated TIWW, suggesting that the isolated bacterium RKS9 has a remarkable potential to effectively decolorize/detoxify TIWW.

Biogenic and eco-benign synthesis of silver nanoparticles using jujube core extract and its performance in catalytic and pharmaceutical applications: Removal of industrial contaminants and in-vitro antibacterial and anticancer activities

Abstract: Biosynthesis of nanoparticles has been rapidly developed in various fields, due to their broad spectrum of applications in the fields of environmental, pharmacology, and medicine. In this study, facile, rapid, eco-friendly and cost-effective method was used to green synthesis of silver nanoparticles (AgNPs) using jujube core extract (AgNPs-JCE) and then used as antibacterial, anticancer and catalytic agents. The reaction parameters such as AgNO 3 concentration (1, 5, 10, 20 and 40 mM), reaction time (5, 30 and 60 min) and pH (without pH, 10 and 12) were discussed and optimized. The surface plasmon resonance peak at about 420 nm in the UV–Vis absorption spectrum confirmed the green synthesis of silver nanoparticles. Microscopic results revealed that the synthesized AgNPs-JCE were spherical in morphology with a size range of 25–35 nm.In addition, the subject AgNPs promising catalytic properties in the degradation of pollutants including rhodamine b (RhB) and eriochrome black T (EBT) as cationic and anionic contaminant under UV and visible light irradiations. The photocatalyst (AgNPs-JCE) exhibited the degradation of 90.9 % and 84.7% for RhB and EBT contaminants after 80 min under UV irradiation, respectively. The antibacterial activities of AgNPs-JCE was checked against E. coli as Gram-positive bacteria and K. pneumoniae and S. aureus as Gram-negative bacteria with MIC and MBC values of (1.26 and 1.26 μ g/ml), (2.5 and 2.5 μ g/ml), and (2.5 and 10 μ g/ml), respectively. Finally, the cytotoxicity of synthesized nanoparticles against AGS as human stomach cancer cell line was determined at several concentrations (2.5, 5, 10, 20, 50, and 100 μ g/ml) using MTT assay. Finding of this research suggested the suitability of AgNPs-JCE as pollutants degradation, antibacterial and anticancer drug development.

Long term trend analysis and suitability of water quality of River Ganga at Himalayan hills of Uttarakhand, India

Abstract: River Ganga flows in the northern part of India and is treated as sacred water resource. The river receive huge amount of partially treated and untreated waste from industrial, agricultural, and religious activities being practiced across the flow, causing deterioration of water quality (WQ) of the river. The present study aims to assess the pollution status and trend of WQ in the river and its primary tributaries (river Bhagirathi and Alaknanda) based on 49 years (1971–2020) data from various locations using water quality index and graphical trend analysis based on a Cartesian coordinate system with 1:1 (45°) line as a benchmark. The results reveal that the WQ in the rivers was good as the estimated values of all WQ parameters were within their permissible limits for drinkable water. The river water was suitable for agriculture activity as sodium-absorption-ratio (SAR) was less than 10 at all sampling-locations. The river WQ was slightly polluted during year 2015–18 as the comprehensive pollution index was in the range of 0.40–1.00. The WQ trend analysis revealed that the parameters pH, Cl − , F − , K + , Na + , SO 4 − 2 , BOD 3 27 , and SAR were altered over time at all sampling-locations. Among all parameters, only SO 4 − 2 concentration gained an incremental trend at all sampling-locations. The decreasing trend of pH and dissolved oxygen concentration was noted at the downstream locations, which reveals that the river WQ might decline if the same scenario remains unchanged in future. The result has implications for the water resource planners, managers, policymakers, and environmentalists responsible for the preservation and restoration of WQ of Ganga and may serve as a strategic model for other major rivers in the region.

Thermal and catalytic pyrolysis of waste polypropylene plastic using spent FCC catalyst

Abstract: Waste polypropylene plastic (WPP) is an enormous volume of plastics in the landfill in Nigeria. It causes serious environmental problems, such as reduced landfill space and pollution. We made WPP plastic undergo pyrolysis using a batch reactor subjected to temperatures variation of 300 °C, 350 °C, 375 °C, 400 °C, and the spent fluid catalytic cracking (FCC) catalyst used were 5, 7.5, and 10 wt% catalyst. We heated the reactor at a rate of 15 °C/min. until it reaches the pyrolysis temperature of 400 °C at atmospheric pressure. We investigated the influence of the FCC catalyst, reaction temperatures, and catalyst to plastic ratio. We characterized the pyrolysis liquid oil using density, pour point, API gravity, flash point, viscosity, calorific value, carbon residue, ATSM distillation, and GC–MS. The thermal pyrolysis produced maximum liquid oil (83.3 wt%) with gases (13.2 wt%), and char (3.0 wt%), while the catalytic pyrolysis using 0.1 catalyst to plastic ratio decreased the liquid oil yield (77.6 wt%), and char (2.7 wt%), with an increase in gases (19.7 wt%). The GC–MS results of the catalytic pyrolysis of liquid oil showed that the liquid fractions comprised a wide range of hydrocarbon, mainly distributed within C4 to > C17. The paraffin, olefins, naphthalene, and aromatics yield were 30.83%, 44.6%. 19.44%, and 5.13%, respectively. The liquid oil’s fuel properties were like that of gasoline and diesel.

Kinetic and thermodynamic investigations of sewage sludge biochar in removal of Remazol Brilliant Blue R dye from aqueous solution and evaluation of residual dyes cytotoxicity

Abstract: Biochar derived from sewage sludge has emerged as an alternative for sustainable utilization as a soil amendment. However, the use of sewage sludge biochar (SSB) has been less explored in the field of wastewater treatment. Therefore, the purpose of this study was to investigate the efficiency of biochar prepared from sewage sludge at 450 °C (SSB-450), as an adsorbent for the removal of Remazol Brilliant Blue R (RBBR) from an aqueous solution. Brunauer–Emmett–Teller (BET), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy were used to characterize SSB-450, with maximum RBBR removal efficiency. The removal of RBBR from aqueous solution by SSB-450 was investigated in batch mode at varying adsorbent dose, contact time, initial RBBR dye concentration temperature and pH. The BET analysis showed the type IV isotherm that indicates the mesoporous structure of SSB-450. The total pore volume and BET specific surface area of SSB-450 particles were found to be 3.936 cm −3/g and 12.447 m2/g, respectively. The RBBR dye adsorption ( q e ) at equilibrium by SSB-450 was found to increase from 8.56 to 80.6 mg g−1 with an increase in initial dye concentration from 10 to 100 mg L−1. The maximum monolayer adsorption capacity (qmax) was 126.59 mg/g of SSB-450, determined by the Langmuir adsorption model. At various RBBR dye concentrations (10 to 100 mg/g), the range of the separation factor ( R L ) was 0.98–0.9, which indicates the favourable adsorption of RBBR dye onto the surface of SSB-450. Besides, Evans blue and triphenyl tetrazolium chloride (TTC) staining of Allium cepa L. roots germinated with dye solutions revealed that biochar treated residual RBBR was non-cytotoxic.