17 research outputs found

    Influence of Microwave and Ultrasound pretreatment on Solvent Extraction of Bio-components from Walnut (Julgans regia L.) Shells

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    Walnut (Julgans regia L.) shells, an agro-forestry waste, are a rich source of phytochemicals with anti-oxidative and medicinal properties. Whilst recent research efforts focus on waste valorization, the present investigation demonstrates a process to extract and characterize bio-components from physically pretreated walnut shells. Pretreatment was undertaken using microwave irradiation and ultra-sonication with two different solvents (methanol and acetone). The extract obtained was optimized using Response Surface Methodology (RSM). Further, the bio-components in the extract were identified using GCMS and FTIR analyses. Through the experimental runs, it was observed that pretreatment enhanced the total extract yield from the process relative to conventional Soxhlet extraction. As a method of pretreatment, microwave irradiation was found to suit the extraction better than ultra-sonication. In addition, acetone performed better as a solvent than methanol in the bio-components recovery. Relative to conventional Soxhlet extraction, microwave pretreatment allowed for enhanced separation by 4.06 folds for methanol and 5.25 for acetone. The yield was found to be the highest (46 mg/g) while using acetone, when pretreated with microwaves at 180 W for 4 min

    The face behind the Covid-19 mask ??? A comprehensive review

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    The threat of epidemic outbreaks like SARS-CoV-2 is growing owing to the exponential growth of the global population and the continual increase in human mobility. Personal protection against viral infections was enforced using ambient air filters, face masks, and other respiratory protective equipment. Available facemasks feature considerable variation in efficacy, materials usage and characteristic properties. Despite their widespread use and importance, face masks pose major potential threats due to the uncontrolled manufacture and disposal techniques. Improper solid waste management enables viral propagation and increases the volume of associated biomedical waste at an alarming rate. Polymers used in single-use face masks include a spectrum of chemical constituents: plasticisers and flame retardants leading to health-related issues over time. Despite ample research in this field, the efficacy of personal protective equipment and its impact post-disposal is yet to be explored satisfactorily. The following review assimilates information on the different forms of personal protective equipment currently in use. Proper waste management techniques pertaining to such special wastes have also been discussed. The study features a holistic overview of innovations made in face masks and their corresponding impact on human health and environment. Strategies with SDG3 and SDG12, outlining safe and proper disposal of solid waste, have also been discussed. Furthermore, employing the CFD paradigm, a 3D model of a face mask was created based on fluid flow during breathing techniques. Lastly, the review concludes with possible future advancements and promising research avenues in personal protective equipment

    Ecological Sanitation and nutrient recovery from human urine: How far have we come? A review

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    To address the shortcomings of modern wastewater treatment, Ecological Sanitation (EcoSan) has been advocated as a sustainable approach to promote closed-loop flows of resources and nutrients from sanitation to agriculture. In this study, we discuss the rationale behind its conception and provide a state-of-the-art review on the subject. Through an exhaustive literature analysis of EcoSan systems, its historical developments and programs implemented worldwide we (i) validate the potential applicability and feasibility of decentralized, source-based sanitation and (ii) depict fundamental problems in EcoSan systems design that have stalled its adoption and proliferation. Specifically, we focus on urine diversion to demonstrate its potential to elegantly separate, collect and concentrate products that we require (nutrients) and those that we wish to regulate (pathogens and micropollutants). Since recent research efforts have been devoted to the technological recovery of nutrients from human urine, we believe that we are witnessing a paradigm shift within a paradigm shift as it represents a change in emphasis from ‘split-stream collection and reuse’ to ‘split-stream collection, resource recovery and safe reuse’. Our analysis of various nutrient recovery technologies for human urine indicates that provisioning of urine-diverting toilets tends to reduce sanitary risks; however, to contain and completely eliminate these risks continued research effort is needed to envision and implement integrated technological pathways that ensure simultaneous nutrient recovery, pathogen inactivation and reduction of pharmaceuticals and active substances

    A Systematic Review on the Synthesis of Silicon Carbide: An Alternative Approach to Valorisation of Residual Municipal Solid Waste

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    Over the past several decades, industrialised and developing nations have attempted to enhance sustainability. Demands for energy and the acceleration in environmental deterioration are the two primary obstacles to progress. The daily generation of municipal solid waste has been a significant factor in the deterioration of the ecology. To address this issue, a considerable amount of municipal solid waste may be used to synthesise SiC nanomaterials from organic and inorganic fractions and use them as carbon and silica sources. Nanomaterials have progressively received widespread prominence as the development of particulate materials accelerates at an incredible rate. One such material is silicon carbide (SiC), which has garnered considerable interest due to its remarkable performance and wide variety of applications. This review article discusses the SiC polytypes, including cubic, hexagonal, and rhombohedral SiC. The characteristics of silicon carbide, such as its biomimetic, surface, and thermal properties, are also discussed. In addition, the synthesis of silicon carbide was described in depth, including microwave sintering, the calcination method, the carbothermal redox reaction, and much more. The final section describes the applications of silicon carbide, including wastewater treatment, medical implants, and gas detection

    Empirical modeling of drying kinetics and microwave assisted extraction of bioactive compounds from Adathoda vasica

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    To highlight the shortcomings in conventional methods of extraction, this study investigates the efficacy of Microwave Assisted Extraction (MAE) toward bioactive compound recovery from pharmaceutically-significant medicinal plants, Adathoda vasica and Cymbopogon citratus. Initially, the microwave (MW) drying behavior of the plant leaves was investigated at different sample loadings, MW power and drying time. Kinetics was analyzed through empirical modeling of drying data against 10 conventional thin-layer drying equations that were further improvised through the incorporation of Arrhenius, exponential and linear-type expressions. 81 semi-empirical Midilli equations were derived and subjected to non-linear regression to arrive at the characteristic drying equations. Bioactive compounds recovery from the leaves was examined under various parameters through a comparative approach that studied MAE against Soxhlet extraction. MAE of A. vasica reported similar yields although drastic reduction in extraction time (210 s) as against the average time of 10 h in the Soxhlet apparatus. Extract yield for MAE of C. citratus was higher than the conventional process with optimal parameters determined to be 20 g sample load, 1:20 sample/solvent ratio, extraction time of 150 s and 300 W output power. Scanning Electron Microscopy and Fourier Transform Infrared Spectroscopy were performed to depict changes in internal leaf morphology

    A holistic review on how artificial intelligence has redefined water treatment and seawater desalination processes

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    In the modern era, deep learning (DL), and machine learning (ML), have emerged as potential technologies that are widely applied in the fields of science, engineering, and technology. These tools have been extensively used to optimize seawater desalination and water treatment processes to achieve efficient performance. Indeed, automation has played a key role in redefining the issues of water treatment and seawater desalination. Artificial intelligence (AI) has been developed as a versatile tool for processing data and optimizing smart water services while addressing the issues of monitoring, management, and labor costs. Recently, specific AI tools, such as artificial neural networks (ANNs) and genetic algorithms, have been implemented for self-monitoring and modeling applications in the field of water treatment and seawater desalination. In the present article, the application of AI in the water treatment and seawater desalination sectors is thoroughly reviewed. Additionally, conventional modeling approaches are compared with ANN modeling. Furthermore, the challenges and shortcomings are discussed, along with future prospects. Moreover, the applications of AI mechanisms in data processing, optimization, modeling, prediction, and decision-making during water treatment and seawater desalination processes are underscored. Finally, innovative trends in seawater desalination and water treatment with AI tools are summarized
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