Shantini A. Bokil

Abstract: It is common for dyes to be utilized in a wide range of industries such as leather and textiles as well as the printing, paper, and packaging industry. Most dyes fall into a dangerous category of water toxins that have had a significant impact on the ecosystem. Dye removal from wastewater can be done in a variety of methods. It is now necessary to develop advanced and cost-effective methods. Organic dyes may be removed from textiles using adsorption, which is a more effective and environmentally beneficial process. Nanomaterials are a more attractive option for dye removal because of their unique characteristics. An approach to the synthesis, characterization, and dye removal capabilities of nano-metal oxides-activated carbons is presented. This review also includes a discussion of several operating parameters associated with the adsorption process, adsorption isotherms, kinetics, thermodynamic behavior, and reusability of the adsorbent.

Abstract: The use of activated carbon (AC) as a strong adsorbent was commonly used. This work deals with the study of textile industry wastewater (dye) adsorption on AC produced from Bamboo and Green coconut shell through chemical activation method. The effect of various process parameters such as the amount of adsorbents, initial concentration of dye, pH, contact time, temperature and agitation speed on percentage removal of dye on the activated carbon i.e. Bamboo activated carbon (BAC) and Green Coconut Shell Activated carbon (GCSAC) batch adsorption tests were investigated. Testing was performed for quantitative description of Langmuir and Freundlich equilibrium adsorption isotherms. Based on the experimental findings, the equilibrium was observed in 6 hours. Langmuir isotherm was the best suited for the adsorption of dye, with a maximal adsorption capacity of 142.86 mg / gm. The removal of dye by the use of BAC has been found to be greater than GCSAC.

Abstract: Nanotechnology opens up new possibilities for food innovation at an incredible rate, yet new technology needs evaluations of both potential negative impacts and numerous good effects. We aimed to cover some of the latest breakthroughs in nanotechnology and their application to food processing in this overview. Applications of nanoparticles in the food sector are growing rapidly. Nanoparticles (NPs) play a significant role in enhancing food quality by protection and preservation and are preferred over traditional preservatives. In this work on organic and inorganic nanoparticles in various forms such as single and multiple metal oxides, polymeric nanocomposite, nanocapsules, etc., as well as various methods of their preparations are discussed. Nanoparticles in food are currently most explored for their antimicrobial applications; factors affecting their antimicrobial potential, their antimicrobial mechanisms, and laboratory methods applied to evaluate antimicrobial potentials are also discussed. Various properties of NPs in relevance to antimicrobial activities and methods used for their characterization are also discussed. Antimicrobial NPs used for the purpose in various ways such as active packaging, mixed in food, incorporated in edible film and coating, etc. discussed. In the current state NPs used in the food industry, have various concerns such as safety, and regulatory policies relevant to preparing, processing, packaging, and consumption are discussed. NPs do possess some functional properties and harmful effects as well in this relevant future perspective of antimicrobial NPs in food and their other applications explored in current work. Various aspects of the most intensively studied NPs as an antimicrobial in food technology such as silver oxide, and zinc oxide, are discussed.

Abstract: Activated carbon prepared from agro-waste material i.e. green coconut shell and bamboo using ZnCl2 as an activation agent in an adsorption column (fixed bed) was studied for the treatment of textile industry effluent. The experiment with the fixed-bed column was performed by different process parameters such as 200, 400 and 600 mg/L as different initial concentration of dye, at different bed heights of 100 mm, 200 mm, and 300 mm, and 10, 15, and 20 mL/min as different flow rates. The findings demonstrated that both breakthrough and exhaust times increase, with the height of the bed being increased, but decrease with the concentration of the dye inlet. The breakthrough point was found to depend upon the bed height and flow rate. The maximum uptake capacity was obtained when a 200 mm bed depth was used at an inlet concentration of dye 200 mg/L with a flow rate of 15 mL/minute. It was observed that the bamboo activated carbon BAC has high carbon content, and has a high potential for dyes removal and may become capable substitutes for costly activated carbon. The adsorption capacities of BAC, GCSAC are at par with respect to each other, the overall process scheme may become economical as these materials are available as wastes and practically free of cost.

Abstract: The existence of pollutants in the water is a very significant environmental problem that needs to be addressed. This work describes the development and testing of activated carbon made from orange peels, which is effective at removing methyl red (MR) from aqueous solutions, and thus provides a solution to this problem. Adsorbents made in the lab can be characterized by their bulk density, particle size, surface area, and proximate analysis. The surface area of the prepared adsorbent was 512.2 m2g−1. Standard procedures such as XRD, SEM, and FTIR analysis are also used to characterize prepared orange peel-activated carbon. Adsorbent dosage (0.25 to 1.25 g/L), MR concentration (100 to 400 mg/L), temperature (40 to 60 °C), contact time (10 to 60 minutes), and pH (3 to 11) were all examined in this experiment. At an amount of adsorbent of 1 g/L adsorbent, MR concentration of 100 mg/L, and a pH of 11, maximum adsorption has been observed. In order to analyze the results, adsorption models such as the Langmuir and Freundlich were applied. At 60 °C, the adsorption isotherm was found to fit the Langmuir model with 111.11 mg/g. The linear regression correlation coefficient, the R2 value is 0.999. Analytical results showed that MR could be effectively removed by using AC made from waste orange peels as an adsorbent.

Abstract: Batik industrial effluent wastewater (BIE) contains toxic dyes that, if directly channeled into receiving water bodies without proper treatment, could pollute the aquatic ecosystem and, detrimentally, affect the health of people. This study is aimed at assessing the adsorptive efficacy of a novel low-cost sewage-sludge-based biochar (SSB), in removing color from batik industrial effluent (BIE). Sewage-sludge-based biochar (SSB) was synthesized through two stages, the first is raw-material gathering and preparation. The second stage is carbonization, in a muffle furnace, at 700 °C for 60 min. To investigate the changes introduced by the preparation process, the raw sewage sludge (RS) and SSB were characterized by the Brunauer–Emmett–Teller (BET) method, Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy. The surface area of biochar was found to be 117.7 m2/g. The results of FTIR showed that some functional groups, such as CO and OH, were hosted on the surface of the biochar. Continuous fixed-bed column studies were conducted, by using SSB as an adsorbent. A glass column with a diameter of 20 mm was packed with SSB, to depths of 5 cm, 8 cm, and 12 cm. The volumes of BIE passing through the column were 384 mL/d, 864 mL/d, and 1680 mL/d, at a flow rate of 16 mL/h, 36 mL/h, and 70 mL/h, respectively. The initial color concentration in the batik sample was 234 Pt-Co, and the pH was kept in the range of 3–5. The effect of varying bed depth and flow rate over time on the removal efficiency of color was analyzed. It was observed that the breakthrough time differed according to the depth of the bed and changes in the flow rates. The longest time, where breakthrough and exhausting points occurred, was recorded at the highest bed and slowest flowrate. However, the increase in flow rate and decrease in bed depth made the breakthrough curves steeper. The maximum bed capacity of 42.30 mg/g was achieved at a 16 mL/h flowrate and 12 cm bed height. Thomas and Bohart–Adams mathematical models were applied, to analyze the adsorption data and the interaction between the adsorption variables. For both models, the correlation coefficient (R2) was more than 0.9, which signifies that the experimental data are well fitted. Furthermore, the adsorption behavior is best explained by the Thomas model, as it covers the whole range of breakthrough curves.

Abstract: Chlorpyrifos is an organophosphate insecticide linked to neurological dysfunctions, endocrine disturbance, cardiovascular illness, genotoxicity, histopathological abnormalities, immunotoxicity, and oxidative stress. Therefore, the aim of this study was to prepare activated carbon from agricultural waste to adsorb and remove chlorpyrifos from aqueous solutions, as well as to study the physicochemical characteristics of the prepared activated carbon.Activated carbon was prepared from agricultural waste (banana peels, orange peels, pomegranate peels and date stones). The activated carbon prepared showed an exterior surface that was irregular and full of cavities with Brunauer-Emmett-Teller(BET) surface areas of 94.26, 111.75, 183.89, and 289.86 m2/g for activated carbon prepared from orange peels, date stone, pomegranate peels, and banana peels respectively. The Scanning Electron Microscope (SEM) image revealed that the activated carbon's exterior surface was irregular and full of various shapes and sizes of cavities.The Energy Dispersive X-Ray (EDX) indicated the existence of carbon, oxygen, silicon and potassium in banana peels-derived activated carbon, whereas carbon, oxygen, silicon and potassium, in addition to aluminium, were detected in the pomegranate peels-derived activated carbon. The Fourier-Transform Infrared Spectroscopy (FTIR) analysis of prepared activated carbon revealed several functional groups, including carboxylic acid, carbon dioxide, and aromatic compounds. Results also showed that the activated carbon significantly removed chlorpyrifos from water, recording 97.6%, 90.6%, 71.48%, and 52.00 % for activated carbon prepared from pomegranate peels, banana peels, date stones and orange peels, respectively. The study concluded that agricultural waste-derived activated carbon could be employed as an alternative pesticide adsorbent.

Abstract: In the context of current environmental, social and economic issues, it is imperative to perform more in-depth studies on waste management and the life cycle of a product. Thus, the concept of circular economy, aimed at transforming traditional patterns of production and economic growth, is extremely important. One way to mitigate negative environmental impacts that is consistent with a circular economic system is to encourage interdisciplinarity between sectors, that is, one production sector can provide a function for waste from another. In this context, this article gathers scientific information on two sectors relevant to the global economy (textiles and food), with the aim of reusing waste from the food industry to manufacture a new textile product with added value. Specifically, the focus is on the use of bacterial cellulose from the probiotic drinks from kombucha, for the manufacture of biotextiles for fashion industry. A discussion is also presented, relating the circular economy concept to the UN Sustainable Development Goals, in order to understand which goals can be achieved with this approach.

Abstract: Continuous waste discharge into natural water resources in many countries is a severe global issue, and seeking an effective solution is a researcher’s concern. Herein, toilet paper waste was a low-cost precursor for preparing carbon nanoparticles (TPCNPs). The characterization of TPCNPs revealed a 30 nm to 50 nm particle size, a 264 m2 g−1 surface area, and a cubical graphite lattice XRD pattern. The TPCNPs were tested for removing malachite green (MG), indigo carmine (IC), rhodamine B (RB), and methylene blue (MB) dyes from water. The solution parameters were examined for the sorption process, and a pH of 5.0 suited the MB removal, while a pH of 6.0 was suitable for MG, IC, and RB. The effect of concentration investigation showed an adsorption capacity of 110.9, 64.8, 73.5, and 98 mg g−1 for MG, IC, RB, and MB, respectively. The sorption of the four dyes fitted the Langmuir isotherm model; it was exothermic and spontaneous. The water remediation was tested using groundwater and seawater samples (GW and SW) spiked with pollutants. It is worth mentioning that one treatment sufficed for the remediation of GW and SW contaminated by 5 mg L−1 concentration, while a double treatment was required for 10 mg L−1 pollution in both samples.

Abstract: It is common for dyes to be utilized in a wide range of industries such as leather and textiles as well as the printing, paper, and packaging industry. Most dyes fall into a dangerous category of water toxins that have had a significant impact on the ecosystem. Dye removal from wastewater can be done in a variety of methods. It is now necessary to develop advanced and cost-effective methods. Organic dyes may be removed from textiles using adsorption, which is a more effective and environmentally beneficial process. Nanomaterials are a more attractive option for dye removal because of their unique characteristics. An approach to the synthesis, characterization, and dye removal capabilities of nano-metal oxides-activated carbons is presented. This review also includes a discussion of several operating parameters associated with the adsorption process, adsorption isotherms, kinetics, thermodynamic behavior, and reusability of the adsorbent.