Evaluating the performance of electrocoagulation system in the removal of polystyrene microplastics from water

Emerging pollutants, particularly microplastics, present a significant threat to both the environment and human health. Traditional treatment methods lack targeted strategies for their removal. This study thoroughly investigated the efficacy of electrocoagulation as a method for efficiently extracting microplastics from water. Various critical operational parameters, including electrode combinations, pH levels, electrolyte concentrations, electrode geometries, configurations, current intensities, and reaction times, were systematically examined. The study systematically examined the impact of different combinations of aluminium (Al) and stainless steel (SS) electrodes, including Al-Al, SS-SS, Al-SS, and SS-Al. Among these combinations, it was found that the Al-Al pairing exhibited outstanding efficiency in microplastic removal, while simultaneously minimizing energy consumption. Initial pH emerged as a critical parameter, with a neutral pH of 7 demonstrating the highest removal efficiency. In the pursuit of optimizing parameters like electrolyte concentrations, electrode geometry, and configuration, it's noteworthy that consistently achieving removal efficiencies exceeding 90% has been a significant achievement. However, to ascertain economic efficiency, additional factors such as energy consumption, electrode usage, and post-treatment conductivity must be taken into account. To tackle the complexity posed by various parameters and criteria, using multi-criteria decision-making tools like TOPSIS is essential, as it has a track record of effectiveness in practical applications. The electrolyte concentration of 0.5 g L-1 is identified as optimal by TOPSIS analysis Additionally, the TOPSIS highlighted the superiority of cylindrical hollow wire mesh electrodes and established the monopolar parallel configuration as the most effective electrode connection method. The investigation carefully evaluated the effect of reaction time, determining that a 50-min window provides optimal microplastic removal efficiency. This refined system exhibited remarkable proficiency in eliminating microplastics of varying size ranges (0-75 μm, 75-150 μm, and 150-300 μm), achieving removal efficiencies of 90.67%, 93.6%, and 94.6%, respectively, at input concentration of 0.2 g L-1. The present study offers a comprehensive framework for optimizing electrocoagulation parameters, presenting a practical and highly effective strategy to address the critical issue of microplastic contamination in aquatic environments.

Environmentally benign approach to formulate nanoclay/starch hydrogel for controlled release of zinc and its application in seed coating of Oryza Sativa plant

Improper use of conventional fertilizers has been linked to adverse effects on soil nutrient levels. To mitigate the negative impact of surface feeding fertilizers and reduce environmental pollution, a new type of seed coating material has been developed to provide nutrients in close proximity to the growing seed. In this study, a biodegradable seed coating film encapsulating micronutrients was fabricated by incorporating montmorillonite into a starch matrix using the melt processing technique. The dispersion of montmorillonite within the starch matrix was examined using X-ray diffraction (XRD), infrared spectroscopy (IR), and thermal gravimetric analysis (TGA). The results revealed polar interactions among starch, silicate layers, and the hydrogel. The XRD analysis demonstrated a shift in the diffraction peak (001) of the Zinc/montmorillonite/starch/glycerol nanocomposite film from 6.2° to 4.9°, indicating the successful intercalation of Zinc, starch, and glycerol. Furthermore, the inclusion of nanoclay improved the thermal stability of the resulting polymer composite and enhanced its ion exchange capacity, water retention, and micronutrient retention. The time-dependent release of zinc micronutrient from the montmorillonite/starch/glycerol composite film was investigated in Zn-deficient soil extract over a 20-day period. The composite film demonstrated extended release behavior of Zn2+. Subsequently, rice seeds were coated with the zinc-containing composite film using a dip-coating method, and their performance in Zn-deficient soil was evaluated. The results indicated that zinc-coated seeds exhibited improved germination percentage, vegetative growth, and yield compared to uncoated seeds.

Recent advances in remediation strategies for mitigating the impacts of emerging pollutants in water and ensuring environmental sustainability

The proliferation of emerging pollutants (EPs), encompassing a range of substances such as phthalates, phenolics, pharmaceuticals, pesticides, personal care products, surfactants, and disinfection agents, has become a significant global concern due to their potential risks to the environment and human well-being. Over the past two decades, numerous research studies have investigated the presence of EPs in wastewater and aquatic ecosystems, with the United States Environmental Protection Agency (USEPA) categorizing these newly introduced chemical compounds as emerging contaminants due to their poorly understood impact. EPs have been linked to adverse health effects in humans, including genotoxic and cytotoxic effects, as well as conditions such as obesity, diabetes, cardiovascular disease, and reproductive abnormalities, often associated with their estrogenic action. Microalgae have shown promise in the detoxification of both inorganic and organic contaminants, and several large-scale microalgal systems for wastewater treatment have been developed. However, the progress of algal bioremediation can be influenced by accidental contaminations and operational challenges encountered in pilot-scale research. Microalgae employ various processes, such as bioadsorption, biouptake, and biodegradation, to effectively remediate EPs. During microalgal biodegradation, complex chemical compounds are transformed into simpler substances through catalytic metabolic degradation. Integrating algal bioremediation with existing treatment methodologies offers a viable approach for efficiently eliminating EPs from wastewater. This review focuses on the use of algal-based biological remediation processes for wastewater treatment, the environmental impacts of EPs, and the challenges associated with implementing algal bioremediation systems to effectively remove emerging pollutants.

Conversion of PET Bottle Waste into a Terephthalic Acid-Based Metal-Organic Framework for Removing Plastic Nanoparticles from Water

Micro- and nanoparticles of plastic waste are considered emerging pollutants with significant environmental and health impacts at high concentrations or prolonged exposure time. Here we report the synthesis and characterization of a known metal-organic framework (MOF) using terephthalic acid (TPA) recovered from the hydrolysis of polyethylene terephthalate (PET) bottle waste. This approach adds value to the existing large amounts of bottle waste in the environment. Fully characterized zinc-TPA MOF (MOF-5) was used for the extraction and removal of engineered polyvinyl chloride (PVC) and polymethylmethacrylate (PMMA) nanoparticles from water with a high efficiency of 97% and 95%, respectively. Kinetic and isotherm models for the adsorption of polymer nanoparticles (PNPs) on the MOF surface were investigated to understand the mechanism. The Qmax for PVC and PMMA NPs were recorded as 56.65 mg/g and 33.32 mg/g, respectively. MOF-5 was characterized before and after adsorption of PNPs on the surface of MOF-5 using a range of techniques. After adsorption, the MOF-5 was successfully regenerated and reused for the adsorption and removal of PNPs, showing consistent results for five adsorption cycles with a removal rate of 83-85%. MOF-5 was characterized before and after adsorption of PNPs on the surface using a range of techniques. The MOF-5 with PNPs on the surface was successfully regenerated and reused for the adsorption and removal of polymer nanoparticles, showing consistent results for five extraction cycles. As a proof of concept, MOF-5 was also used to remove plastic particles from commercially available body scrub gel solutions. Such methods and materials are needed to mitigate the health hazards caused by emerging micro- and nanoplastic pollutants in the environment.

Methyl orange dye adsorbed biochar as a potential Brønsted acid catalyst for microwave-assisted biodiesel production

Biodiesel production from non-edible oils utilizing a highly efficient eco-friendly catalyst is a crucial necessity for replacing fossil fuels. In the present work, biochar has been applied for both energy and environmental purposes. The biochar was made by slow pyrolysis from a variety of biomass, primarily cassava peel, irul wood sawdust, and coconut shell. All biochars were used as adsorbents to remove an anionic dye (methyl orange) by conducting batch adsorption studies. The biochar made from cassava peels showed the highest dye adsorption, and it was characterized using elements analysis (CHNS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), surface area analyzer (BET), total acid density, and sulfonic acid group density to successfully confirm the presence of weak (-OH) and strong (-COOH, -SO3H) acidic groups. Furthermore, for microwave-assisted biodiesel production from Millettia pinnata seed oil, the dye adsorbed biochar made from cassava peel was utilized as a Brønsted acid catalyst. The catalyst having a surface area of 4.89 m2/g, an average pore width of 108.77 nm, a total acid density of 3.2 mmol/g, and a sulfonic acid group density of 1.9 mmol/g exhibits distinctive mesoporous properties that contribute to a biodiesel yield of 91.25%. By utilizing the catalyst for three more cycles and getting a yield of more than 75%, the reusability of the catalyst was investigated.

Microplastics in the environment: An urgent need for coordinated waste management policies and strategies

Microplastics (MPs) have become a prevalent environmental concern, exerting detrimental effects on marine and terrestrial ecosystems, as well as human health. Addressing this urgent issue necessitates the implementation of coordinated waste management policies and strategies. In this study, we present a comprehensive review focusing on key results and the underlying mechanisms associated with microplastics. We examine their sources and pathways, elucidate their ecological and human health impacts, and evaluate the current state of waste management policies. By drawing upon recent research and pertinent case studies, we propose a range of practical solutions, encompassing enhanced recycling and waste reduction measures, product redesign, and innovative technological interventions. Moreover, we emphasize the imperative for collaboration and cooperation across sectors and jurisdictions to effectively tackle this pressing environmental challenge. The findings of this study contribute to the broader understanding of microplastics and provide valuable insights for policymakers, researchers, and stakeholders alike.

Enhanced biodiesel production from waste cooking palm oil, with NaOH-loaded Calcined fish bones as the catalyst

The present work mainly focuses on the development of heterogeneous catalysts from fishbone, loaded with sodium hydroxide for transesterification of biodiesel. The catalyst was developed using a two-step process involving the calcination of fishbone at 900 °C, followed by a hydrothermal process with a sodium hydroxide-loaded (NaOH) solution. The synthesized heterogeneous catalyst was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), and BET surface area analysis. The transesterification of waste cooking palm oil (WCO) with BC-NaOH shows a maximum yield of up to 98% for 2.5 wt.% catalyst loading, 1:9 oil:methanol molar ratio at a temperature of 65 °C for a reaction time of 1.5 h. The enhanced catalytic activity is due to the high base active site density of hydroxyl groups from hydroxyapatite, β- tricalcium phosphate, and sodium hydroxide. A gas chromatography-mass spectroscopy (GC-MS) was performed to determine the conversion of oil to biodiesel. The reusability of the catalyst was confirmed from the consistency in the biodiesel yield obtained in up to 7 cycles.