Showing papers by "Adama University published in 2021"

Evaluation of drinking and irrigation suitability of groundwater with special emphasizing the health risk posed by nitrate contamination using nitrate pollution index (NPI) and human health risk assessment (HHRA)

Abstract: Groundwater is widely recognized as an essential source of water for drinking and irrigation uses in the South India. It is essential to evaluate the characterization of groundwater for drinking an...

Emerging and Re-emerging Vector-Borne Infectious Diseases and the Challenges for Control: A Review.

Abstract: Vector-borne emerging and re-emerging diseases pose considerable public health problem worldwide. Some of these diseases are emerging and/or re-emerging at increasing rates and appeared in new regions in the past two decades. Studies emphasized that the interactions among pathogens, hosts, and the environment play a key role for the emergence or re-emergence of these diseases. Furthermore, social and demographic factors such as human population growth, urbanization, globalization, trade exchange and travel and close interactions with livestock have significantly been linked with the emergence and/or re-emergence of vector-borne diseases. Other studies emphasize the ongoing evolution of pathogens, proliferation of reservoir populations, and antimicrobial drug use to be the principal exacerbating forces for emergence and re-emergence of vector-borne infectious diseases. Still other studies equivocally claim that climate change has been associated with appearance and resurgence of vector-borne infectious diseases. Despite the fact that many important emerging and re-emerging vector-borne infectious diseases are becoming better controlled, our success in stopping the many new appearing and resurging vector-borne infectious diseases that may happen in the future seems to be uncertain. Hence, this paper reviews and synthesizes the existing literature to explore global patterns of emerging and re-emerging vector-borne infections and the challenges for their control. It also attempts to give insights to the epidemiological profile of major vector-borne diseases including Zika fever, dengue, West Nile fever, Crimean-Congo hemorrhagic fever, Chikungunya, Yellow fever, and Rift Valley fever.

Milk adulterant detection: Conventional and biosensor based approaches: A review

Abstract: Milk adulteration is one of the major global concerns as milk is being consumed as a wholesome dairy product in every part of the world. The fraudulent practice of milk adulteration is on the rise, which is making people apprehensive about the purity and quality of milk. The adulterants such as water, vegetable and animal fat, extraneous proteins and chemical components viz. melamine, urea, formalin, detergents, ammonium sulphate, boric acid, caustic soda, benzoic acid, salicylic acid, hydrogen peroxide and sugars deliberately mixed in milk can be an be harmful to the health of consumers. This necessitates the availability of procedures and technologies that could curb this ill practice of milk adulteration. Over the years, various methods have been developed for the detection of milk adulterants. The chromatographic methods such as HPLC and GC, coupled with mass spectrometry have been used for selective identification as well as detection of different milk adulterants. Immunological techniques such as ELISA and various DNA based procedures like PCR have also been used for the specific detection of some common milk adulterants. Spectroscopic methods, namely FTIR and NIR in association with chemometrics have raised the bar of adulterant detection systems. The equipments such as electronic nose and electronic tongue are some of the fancy procedures used in milk and other food adulterants detection. The biosensors are the detection systems that can be used for rapid and real time detection of milk adulterants. This review brings insight into the biosensor application in milk adulterant detection and also tries to explore the potential of biosensors in identifying some common milk adulterants.

Land use/land cover changes and their impact on land surface temperature using remote sensing technique in district Khanewal, Punjab Pakistan

Abstract: The aim of this research was to assess the land use/land cover (LULC) changes and its impact on land surface temperature (LST) using remote-sensing (RS) technique in the district Khanewal, Punjab, ...

DFD-Net: lung cancer detection from denoised CT scan image using deep learning

Abstract: The availability of pulmonary nodules in CT scan image of lung does not completely specify cancer. The noise in an image and morphology of nodules, like shape and size has an implicit and complex association with cancer, and thus, a careful analysis should be mandatory on every suspected nodules and the combination of information of every nodule. In this paper, we introduce a “denoising first” two-path convolutional neural network (DFD-Net) to address this complexity. The introduced model is composed of denoising and detection part in an end to end manner. First, a residual learning denoising model (DR-Net) is employed to remove noise during the preprocessing stage. Then, a two-path convolutional neural network which takes the denoised image by DR-Net as an input to detect lung cancer is employed. The two paths focus on the joint integration of local and global features. To this end, each path employs different receptive field size which aids to model local and global dependencies. To further polish our model performance, in different way from the conventional feature concatenation approaches which directly concatenate two sets of features from different CNN layers, we introduce discriminant correlation analysis to concatenate more representative features. Finally, we also propose a retraining technique that allows us to overcome difficulties associated to the image labels imbalance. We found that this type of model easily first reduce noise in an image, balances the receptive field size effect, affords more representative features, and easily adaptable to the inconsistency among nodule shape and size. Our intensive experimental results achieved competitive results.

Groundwater Pollution and Human Health Risks in an Industrialized Region of Southern India: Impacts of the COVID-19 Lockdown and the Monsoon Seasonal Cycles.

Abstract: Samples of groundwater were collected during a post-monsoon period (January) and a pre-monsoon period (May) in 2020 from 30 locations in the rapidly developing industrial and residential area of the Coimbatore region in southern India. These sampling periods coincided with times before and during the lockdown in industrial activity and reduced agricultural activity that occurred in the region due to the COVID-19 pandemic. This provided a unique opportunity to evaluate the effects of reduced anthropogenic activity on groundwater quality. Approximately 17% of the wells affected by high fluoride concentrations in the post-monsoon period returned to levels suitable for human consumption in samples collected in the pre-monsoon period. This was probably due to ion exchange processes, infiltration of rainwater during the seasonal monsoon that diluted concentrations of ions including geogenic fluoride, as well as a reduction in anthropogenic inputs during the lockdown. The total hazard index for fluoride in the post-monsoon samples calculated for children, adult women, and adult men indicated that 73%, 60%, and 50% of the groundwater samples, respectively, had fluoride levels higher than the permissible limit. In this study, nitrate pollution declined by 33.4% by the pre-monsoon period relative to the post-monsoon period. The chemical facies of groundwater reverted from the Na-HCO3-Cl and Na-Cl to the Ca-HCO3 type in pre-monsoon samples. Various geogenic indicators like molar ratios, inter-ionic relations along with graphical tools demonstrated that plagioclase mineral weathering, carbonate dissolution, reverse ion exchange, and anthropogenic inputs are influencing the groundwater chemistry of this region. These findings were further supported by the saturation index assessed for the post- and pre-monsoon samples. COVID-19 lockdown considerably reduced groundwater pollution by Na+, K+, Cl-, NO3¯, and F- ions due to shutdown of industries and reduced agricultural activities. Further groundwater quality improvement during lockdown period there is evidence that the COVID-19 lockdown by increased HCO3¯ ion concentration. Overall results illustrate the positive benefits to groundwater quality that could occur as a result of measures to control anthropogenic inputs of pollutants.

A review on environmentally benevolent synthesis of CdS nanoparticle and their applications

Abstract: The word ‘Nano’ received great attention of world, due to their fabulous and novel applications in numerous fields. Cadmium sulphide nanoparticles (CdS NPs) are unique in their properties due the size and shape, and are popular in the area of biosensor, bio-imaging, nano-medicine, molecular pathology, antimicrobial activities, photovoltaic cells, semiconductor, and drug delivery, etc. Due to its fascinating applications, it was synthesized using several methods and explored for its all possible applications. The most affordable, efficient, friendly and biocompatible way of creation of CdS NPs is biogenic synthesis using microorganisms such as bacteria, fungus, algae, enzymes, proteins and parts of plants. In biogenic synthesis of CdS, cadmium undergoes bio-reduction by the variety of natural products present in microorganism as well as in plants. In present review, inclusive study was piloted on the nano-synthesis, characterization and various applications of CdS NPs made using different plant sources and microorganism.

Potential Human Health Risks Due to Groundwater Fluoride Contamination: A Case Study Using Multi-techniques Approaches (GWQI, FPI, GIS, HHRA) in Bilate River Basin of Southern Main Ethiopian Rift, Ethiopia

Abstract: The main focus of the present research was to examine the appropriateness of groundwater resources for drinking purposes in the Bilate River Basin of Southern Main Ethiopian Rift, Ethiopia. The groundwater quality index (GWQI), fluoride pollution index (FPI), and human health risk were used to examine the human health risk factors associated with the intake of high fluoride groundwater. For this purpose, 29 groundwater samples were collected from the existing wells and were analyzed for various physicochemical parameters. The dominant cation was Na+, followed by Ca2+, Mg2+, and K+. The dominant anion was HCO3−, followed by Cl−, SO42−, and F−. The Gibbs plot shows that rock-water interactions are the dominant factor controlling the groundwater chemistry. By using the GWQI, the quality of groundwater samples was 31% excellent, 21% good, 31% poor, and 17% very poor. The fluoride concentration in groundwater ranges from 0.2 to 5.60 mg/L (mean, 2.10 mg/L). 59% (i.e., 17 wells) of the groundwater samples were not suitable for drinking, because they surpassed the drinking water quality limit of 1.5 mg/L. The remaining 41% (i.e., 12 wells) of the samples were suitable for drinking. The FPI indicates that 51.72% of the wells were highly polluted by fluoride. The noncarcinogenic health risk varies from 0.75 to 8.44 for children (83%), 0.34–3.84 for women (62%), and 0.27–3.01 for men (52%), which indicates that children are at higher health risk than women and men due to the physiological condition and the rates of ingestion.

Hybrid process of electrocoagulation and electrooxidation system for wastewater treatment: A review

Abstract: Water is one of the most essential natural resources required for all living things. Globally, due to various factors, the volume of wastewater generated and contaminant loads are increasing. Therefore, currently, there is high interest and concern in developing more effective wastewater treatment technologies. Particularly, the emerging electrochemical methods, mainly electrocoagulation (EC), electrooxidation (EO), and the hybrid of both EC and EO, have recently attracted attention as a potential method for treating wastewater due to its wide application and environmental compatibility. In the EC process, different metal hydroxide species are formed. The metal hydroxides (coagulant) aggregate the dispersed particles in the solution, which forms bigger flocs and then is removed by sedimentation. In most cases, EC is not able to reduce the stable persistent organic compounds to below the allowable discharge limits. Also, the EO process is an emerging process where contaminants are removed by oxidizing directly at the surface of the electrode or indirectly by generating oxidants in the solution. However, the main drawback of the EO method is that it is not applicable or requires a long operation time for treating water and wastewater with large amounts of suspended solids. Thus, to use the EO treatment system, the suspended solids of the wastewater have to be removed first by using other techniques. This can be achieved by a hybrid process of EC and EO. Besides, the hybrid process can enhance the removal of COD, TOC, NH4+-N, nitrates, phenol, which is not effectively achieved by using only EC or EO. Therefore, in this particular review, special emphasis was given to a hybrid of EC and EO processes, in addition to assessing electrocoagulation and electrooxidation as exceptional electrochemical methods. Even though several studies have covered EC, EO, and a hybrid process of EC and EO systems separately, to our best knowledge, there is an extremely limited number of review papers that have been done on the hybrid process of EC and EO. Therefore, this manuscript aims to review the potential of a hybrid of the EC and EO processes for treating wastewater generated from various sources.

Multi-objective optimization modelling of sustainable green supply chain in inventory and production management

Abstract: The ever increasing pressure to conserve the environment from global warming cannot be overemphasized. Emission from the inventory and production process contributes immensely to global warming and hence, the need to device a sustainable green inventory by the operational managers. In this paper, a multi-item multi-objective inventory model with back-ordered quantity incorporating green investment in order to save the environment is proposed. The model is formulated as a multi-objective fractional programming problem with four objectives: maximizing profit ratio to total back-ordered quantity, minimizing the holding cost in the system, minimizing total waste produced by the inventory system per cycle and minimizing the total penalty cost due to green investment. The constraints are included with budget limitation, space restrictions, a constraint on cost of ordering each item, environmental waste disposal restriction, cost of pollution control, electricity consumption cost during production and cost of greenhouse gas emission in the production process. The model effectiveness is illustrated numerically, and the solution obtained to give a useful suggestion to the decision-markers in the manufacturing sectors.

Multifunctional application of PVA-aided Zn-Fe-Mn coupled oxide nanocomposite.

Abstract: Zinc oxide (ZnO) is a fascinating semiconductor material with many applications such as adsorption, photocatalysis, sensor, and antibacterial activities. By using a poly (vinyl alcohol) (PVA) polymer as a capping agent and metal oxides (iron and manganese) as a couple, the porous PVA-aided Zn/Fe/Mn ternary oxide nanocomposite material (PTMO-NCM) was synthesized. The thermal, optical, crystallinity, chemical bonding, porosity, morphological, charge transfer properties of the synthesized materials were confirmed by DTG/DSC, UV–Vis-DRS, XRD, FT-IR, BET, SEM-EDAX/TEM-HRTEM-SAED, and CV/EIS/amperometric analytical techniques, respectively. The PTMO-NCM showed an enhanced surface area and charge transfer capability, compared to ZnO. Using the XRD pattern and TEM image analysis, the crystalline size of the materials was confirmed to be in the nanometer range. The porosity and superior charge transfer capabilities of the PTMO-NCM were confirmed from the BET, HRTEM (IFFT)/SAED, and CV/EIS analysis. The adsorption kinetics (adsorption reaction/adsorption diffusion) and adsorption isotherm test confirmed the presence of a chemisorption type of adsorbate/methylene blue dye-adsorbent/PTMO-NCM interaction. The photocatalytic performance was tested on the Congo red and Acid Orange-8 dyes. The superior ascorbic acid sensing capability of the material was understood from CV and amperometric analysis. The noble antibacterial activities of the material were also confirmed on both gram-negative and gram-positive bacteria.

Photocatalytic degradation of organic dyes: Pd-γ-Al2O3 and PdO-γ-Al2O3 as potential photocatalysts

Abstract: This work describes photocatalytic application of γ-alumina (γ-Al2O3) surface-anchored palladium and palladium oxide nanoparticles (Pd-γ-Al2O3 and PdO-γ-Al2O3 NPs) synthesized by a novel co-precipitation technique. The palladium(0) NPs (Pd-γ-Al2O3) were formed by calcination of the sample in inert medium, whereas PdO NPs (PdO-γ-Al2O3) were obtained by calcination of the sample in atmospheric oxygen. As-synthesized Pd-γ-Al2O3 and PdO-γ-Al2O3 NPs are characterized by X-ray diffraction, Fourier transform-infrared spectroscopy, field emission scanning electron microscopy and photoluminescence (PL) spectra. The PL spectra of Pd-γ-Al2O3 and PdO-γ-Al2O3 NPs display visible-light emissions from 450 to 500 nm at room temperature. This work aims to study the photocatalytic degradation of organic dye pollutants, including bromocresol green (BCG), bromothymol blue, methylene blue and methyl orange using Pd-γ-Al2O3 and PdO-γ-Al2O3 NPs as potential photocatalysts. Experimental parameters, including the admitting concentration of the organic dye solution, Pd-γ-Al2O3 and PdO-γ-Al2O3 photocatalyst dosage, and pH, were varied to ascertain favorable conditions for photocatalytic degradation. The results indicate that the organic dye BCG is completely (100%) degraded in aqueous solution under ultraviolet light, compared with the other organic dyes. Furthermore, Pd-γ-Al2O3 NPs showed better photocatalytic performance than PdO-γ-Al2O3 NPs. The possible photocatalytic degradation mechanism of the organic dyes by Pd-γ-Al2O3 and PdO-γ-Al2O3 photocatalysts is proposed. The studies reveal that Pd and PdO NPs anchored on the γ-Al2O3 surface are promising and effective catalysts for photocatalytic degradation of organic dyes.

The current status, challenges and prospects of using biomass energy in Ethiopia.

Abstract: Despite enormous challenges in accessing sustainable energy supplies and advanced energy technologies, Ethiopia has one of the world's fastest growing economies. The development of renewable energy technology and the building of a green legacy in the country are being prioritized. The total installed capacity for electricity generation in Ethiopia is 4324.3 MW as on October, 2018. Renewable energy accounts for 96.5% of total generation; however, despite the county's enormous biomass energy potential, only 0.58% of power is generated using biomass. Ethiopia has surplus woody biomass, crop residue and animal dung resources which comprise about 141.8 million metric tons of biomass availability per year. At present the exploited potential is about 71.9 million metric tons per year. This review paper provides an in-depth assessment of Ethiopia's biomass energy availability, potential, challenges, and prospects. The findings show that, despite Ethiopia's vast biomass resource potential, the current use of modern energy from biomass is still limited. As a result, this study supports the use of biomass-based alternative energy sources without having a negative impact on the socioeconomic system or jeopardizing food security or the environment. This finding also shows the challenges, opportunities and possible solutions to tackle the problem to expand alternative energy sources. The most effective techniques for producing and utilizing alternate energy sources were also explored. Moreover, some perspectives are given based on the challenges of using efficient energy production and sustainable uses of biomass energy in Ethiopia as it could be also implemented in other developing countries. We believe that the information in this review will shed light on the current and future prospects of biomass energy deployment in Ethiopia.

Removal of Methylene Blue Dye from Wastewater Using Periodiated Modified Nanocellulose

Abstract: The study was focused on the preparation and characterizations of sodium periodate-modified nanocellulose (NaIO4-NC) prepared from Eichhornia crassipes for the removal of cationic methylene blue (MB) dye from wastewater (WW). A chemical method was used for the preparation of NaIO4-NC. The prepared NaIO4-NC adsorbent was characterized by using X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscope (SEM), energy-dispersive X-ray (EDX), and Brunauer–Emmett–Teller (BET) instruments. Next, it was tested to the adsorption of MB dye from WW using batch experiments. The adsorption process was performed using Langmuir and Freundlich isotherm models with maximum adsorption efficiency (qmax) of 90.91 mg·g−1 and percent color removal of 78.1% at optimum 30 mg·L−1, 60 min., 1 g, and 8 values of initial concentration, contact time, adsorbent dose, and solution pH, respectively. Pseudo-second-order (PSO) kinetic model was well fitted for the adsorption of MB dye through the chemisorption process. The adsorption process was spontaneous and feasible from the thermodynamic study because the Gibbs free energy value was negative. After adsorption, the decreased values for physicochemical parameters of WW were observed in addition to the color removal. From the regeneration study, it is possible to conclude that NaIO4-NC adsorbent was recyclable and reused as MB dye adsorption for 13 successive cycles without significant efficient loss.

Effect of various factors and diverse approaches to enhance the performance of solar stills: a comprehensive review

Abstract: The need for fresh drinking water is increasing rapidly, and drinking water availability reduces day by day. Solar desalination is a viable option to change saltwater to fresh drinkable water. Solar still used for desalination includes processes like heating, evaporation, and condensation. The major problem faced by solar stills is that they have low productivity. Therefore, high demand for freshwater cannot be met. The present review aims to provide the researchers with an idea to select suitable methods for enhancing solar stills' performance. This article mainly focuses on the climatic, design, and operational parameters affecting the performance of solar stills. Results reveal that a combination of the incredible intensity of solar radiations, solar still type, and regions with optimum temperature can provide higher daily distillate output. Further, high productivity can be achieved with inclined solar stills by making an inclination angle equivalent to the location's latitude. A water depth of around 1 cm can provide the best output in terms of productivity for conventional solar stills. A combination of V-corrugated absorber plate with fins and energy storing materials coupled with external reflector plates can provide optimized conditions to enhance productivity. The performance of solar still can be improved by minimizing the gap between absorber plates and condensing cover. Finally, the sun tracking system, either single or dual axis in solar still, can enhance productivity.

Advanced techniques to remove phosphates and nitrates from waters: a review

Abstract: At high levels, phosphates and nitrates from mineral fertilizers and wastewaters are contaminating natural waters, leading, for example, to eutrophication and death of many living species. This requires remediation techniques such as physical, chemical, biological methods, and nano-techniques. For instance, microbes such as Bacillus subtilis, Pseudomonas, Achromobacter, Spirulina platensis and Chlorella vulgaris allow denitrification and can remove 55% of phosphates. Removal can be done also using adsorbents produced from wastes and bio-sorbents. Here we compare the methods to remove phosphates and nitrates in waters.

Synthesis of Poly(vinyl alcohol)-Aided ZnO/Mn2O3 Nanocomposites for Acid Orange-8 Dye Degradation: Mechanism and Antibacterial Activity.

Abstract: Zinc oxide is one of the novel metal oxides utilized for diverse applications. The sol-gel and unintended self-propagation procedures were applied to synthesize the porous and high surface area ZnO-based metal oxide nanocomposite. The p-type manganese(III) oxide was successfully coupled with n-type ZnO. The physical property characterization results revealed the surface area, porosity, and charge transfer capability improvement on the poly(vinyl alcohol) (PVA)-aided binary nanocomposite (PVA-ZnO/Mn2O3), compared to ZnO. The XRD patterns and TEM image analysis validated the nanometer size range for the materials (15-60 nm). The SEM micrographs and BET spectral details have confirmed the porous nature of the PVA-ZnO/Mn2O3 nanocomposite. The supporting results were obtained from the HRTEM (IFFT) and SAED pattern analyses. The EDX and HRTEM analyses were used for the confirmation of elemental composition and reality of the PVA-ZnO/Mn2O3 composite, respectively. The presence of the improved charge transfer property for PVA-ZnO/Mn2O3, compared to ZnO, was evidenced from acid orange-8 dye degradation. The highest zone of inhibition (14 mm) was recorded on Escherichia coli bacteria for the uncalcined PVA-ZnO/Mn2O3 nanocomposite compared to PVA, yet, less zone of inhibition compared to the calcined PVA-ZnO/Mn2O3 nanocomposite. The authors recommend the formation of the couple between metal oxides by electrochemical technique analyses as a future work.

Calcium oxide nanoparticles synthesis from hen eggshells for removal of lead (Pb(II)) from aqueous solution

Abstract: Lead is an important industrial heavy metal used in various production industries. Remediation of Lead poisoned areas has both economical and technological challenges, as conventional and techniques are very expensive to apply for wastewater treatment and its operation is difficult. The adsorption method could solve the problem using sol-gel-based synthesized adsorbent since it is environmentally friendly with high-quality product produced. In the present study, the application of synthesized calcium oxide nanoparticles from hen eggshells for the removal of lead ions from aqueous solutions is what was investigated. Characterization of the adsorbent like proximate analysis, particle density, bulk density, porosity, point of zero charges, Fourier transform infrared radiation spectroscope, X-ray diffraction, specific surface area, thermal gravimetric analysis, and scanning electron microscopy was done before batch adsorption experiments. X-ray diffraction revealed that the size of synthesized calcium oxide nanoparticles was 24.34 nm and the specific surface area was 77.4m2/g. The removal of divalent lead ions from aqueous solutions was optimized by using response surface methodology. The optimum percent removal of lead (99.07) has resulted at initial concentration 75.46 ppm, pH 6.94, adsorbent dose 0.838 g, and contact time 101.97 min. The experimental removal efficiency (98.86%) agreed very well with the predicted one (99.07%), showing the suitability of the model used and the success of response surface methodology in optimizing of removal of Pb (II) ions from aqueous solutions. The lead ions removal was well fitted into the Langmuir isotherm model with correlation coefficients of 0.9963. The adsorption kinetic data were well fitted with the pseudo-second-order model with a correlation coefficient of 0.9982. The pseudo-second-order model was the rate-limiting step in the lead (II) ions adsorption process onto CaO NPs. Based on the obtained results, the calcium oxide nanoparticles prepared from eggshell have a good capacity for the removal of the lead ions from the aqueous solutions.

Spherical nanoflower-like bimetallic (Mo,Ni)(S,O)3-x sulfo-oxide catalysts for efficient hydrogen evolution under visible light

Abstract: Photocatalytic H2O splitting by sulfide-based materials is a great challenge, because of the poor resilience of such materials against hole oxidation. Although sulfide ion of catalyst negatively shifts the valence band-edge relative to its oxide ion, the instability of sulfide ions during H2O oxidation is a critical obstacle to simultaneous evolution of H2 and O2. Here, active, stable, and spherical nanoflower-like bimetal (Mo,Ni)(S,O)3-x sulfo-oxide catalysts with a band gap of ∼2.1 eV and different concentrations of oxygen vacancy defects were synthesized for H2O splitting. (Mo,Ni)(S,O)3-x of 25 mg with a suitable amount of oxygen vacancy defects could evolve 587.5 μmol/h H2 under visible-light irradiation. This work demonstrated an example of converting an oxidation photocatalyst into a reduction one. Microstructure analysis showed that surface oxygen vacancy defects and the multiple-valence charges in Ni and Mo not only promoted effective separation, interface transfer, and reactions of photo-carriers but also reduced the charge build-up to avoid photo-corrosion during photocatalytic water decomposition.

Carbon and metal-based catalysts for vanadium redox flow batteries: a perspective and review of recent progress

Abstract: As one of the most promising electrochemical energy storage systems, vanadium redox flow batteries (VRFBs) have received increasing attention owing to their attractive features for large-scale storage applications. However, their high production cost and relatively low energy efficiency still limit their feasibility. One of the critical components of VRFBs that can significantly influence the effectiveness and final cost is the electrode. Therefore, the development of an ideal electrocatalyst with low cost, high electrical conductivity, large active surface area, good chemical stability, and excellent electrochemical reaction activity toward the VO2+/VO2+ and V2+/V3+ redox reactions is essential for the design of VRFBs. Extensive research has been carried out on electrode modification routes for VRFBs to improve the energy density and overall performance for large-scale applications. This review article focuses on numerous state-of-the-art modification methods for VRFB electrodes, including those based on carbon materials, metal and metal oxide-based materials, and metal oxide/carbon composite materials. The challenges in the development of electrode materials and future research directions are also proposed.

Enhanced multifunctionality of CuO nanoparticles synthesized using aqueous leaf extract of Vernonia amygdalina plant

Abstract: We report the synthesis of medicinal plant, Vernonia amygdalina Del. mediated green copper oxide nanoparticles (VeA-CuO NPs). The presence of two absorbance maxima, λmax 1 and λmax 2 at 436 nm and 452 nm, respectively confirms a mixture of biomolecules surface amalgamated CuO NPs with different morphological features. The FT-IR spectra of the plant leaf extract and VeA-CuO confirmed the efficient role of biomolecules as capping and stabilising agents. The XRD patterns of NPs approved high crystallinity of CuO. The purity of the NPs was corroborated by SEM-EDAX analysis. The average particle size of the NPs was found to be 19.68 nm. In addition, the combined TEM, HRTEM and SAED analysis substantiated the presence of CuO with a d-spacing value of 0.2854 nm, which conformed to CuO (1 1 1). The antibacterial assay revealed that VeA-CuO NPs were synergistic in their influence versus bacterial strains, S. aureus, E. coli, P. aeruginosa, and E. aerogenes. The uppermost zone of inhibition of 15 mm was observed for E. aerogenes. The bioactive compounds capped around the CuO NPs served the effective role in disrupting the cell wall of bacterial strains. The degradation efficiencies for Indigo carmine (IC) and Malachite green (MG) dyes by NPs were found to be 95% and 91%, respectively. The lowest degradation half-life was recorded to be 16.55 min for MG dye. In addition, the better electrode stability revealed by CV and EIS studies, confirms the multi-functional nature of VeA-CuO NPs, these CuO NPs exhibited multifunctional applications.

Geochemical evaluation and human health risk assessment of nitrate-contaminated groundwater in an industrial area of South India

Abstract: The primary goal of this study is to evaluate the groundwater quality and conduct a non-carcinogenic risk assessment of nitrate contamination in an industrialized and high-density region of South India. A total of 40 sampling sites were identified in and around the industrial area, and samples were collected during the pre-monsoon and post-monsoon seasons. Piper and Gibbs’ diagram shows that rock-water interaction, lithological characteristics and ion-exchange processes are the primary factors determining groundwater quality. The novel entropy water quality index (EWQI) indicated that 32 and 37.5% of the water in the study area were unsuitable for drinking purposes during both the pre-monsoon and post-monsoon seasons, respectively. Due to landfill leachate and modern agricultural activity, the nitrate concentration in groundwater post-monsoon had increased by 17.11%. The nitrate pollution index (NPI) value of groundwater exceeded the contaminated level by 22.77%. The non-carcinogenic human health risk assessment revealed that 35 and 40% of adult males, 37.5 and 52.5% of adult females and 42.5 and 55% of children during the pre-monsoon and post-monsoon periods were exposed to an increased concentration of nitrate in groundwater. The non-carcinogenic risk level to the exposed population in the study region descends in the following order: children > > females > males. The study suggests that low body weight in children is a direct result of consumption of low-quality water and that adult men and women suffer less severe consequences.

Investigation of direct and alternating current–electrocoagulation process for the treatment of distillery industrial effluent: Studies on operating parameters

Abstract: The main objective of this study is to analyze the influence of direct and alternating – current on electrocoagulation process in terms of % color and % COD removal along with electrical energy consumption from distillery industrial effluent. The percentage of color and COD removal and electrical energy consumption were about 90.57%, 86.54% and 3.50 kWhr/m3 with Direct – Current Electrocoagulation (DCE). For Alternating – Current Electrocoagulation (ACE), it was 100%, 95% and 3.20 kWhr/m3, respectively at the optimal experimental condition of COD – 3000 mg/L, initial wastewater pH – 7, current density – 0.4 A/dm2, inter–electrode spacing – 1 cm, combination of electrode – Fe/Fe, pulse duty cycle – 0.45, frequency – 50 Hz and treatment time – 3.5 h. The ACE was more successful in eliminating % color and % COD with less electrical energy consumption than DCE process. In DCE, the formation of an impermeable oxide layer on the cathode and the occurrence of corrosion on the anode due to oxidation have decreased the efficiency of this process compared to the ACE process. As a result, experimental findings have shown that with less electrical energy usage and process efficiency, the ACE could be a more promising solution to removing pollutants from wastewater and industrial effluent than the DCE method.