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•Production of biochar produced through pyrolysis of lignocellulosic biomass has been narrated.•The factors influencing pyrolytic conditions and pyrolytic conversion have been ...discussed.•Reviewed the modification of biochar and mechanism of pollutant adsorption using biochar.•Potential positive aspects of biochar applications towards pollutant removal are also discussed.
Thermochemical processing of biomass results in a producing char, a typical by-product. The char can be termed as biochar when specifically applied as a soil fertility enhancement. Biochar, when utilized efficiently, is basic for enhancing financial viability and also to maintain ecosystem. The properties of carbonized biomass rely upon raw materials (feedstock) and procedure conditions. Biochar shows an incredible potential to effectively handle water contaminants taking into consideration the wide accessibility of feedstock, suitable physical/chemical surface properties and low-cost. Pyrolysis technology for converting lignocellulosic biomass into biochar has emerged as a frontier research domain for the removal of pollutants. This review focused on production of biochar from various sources of lignocellulosic biomass (cellulose, hemicellulose and lignin) and its application in various fields such as agriculture, wastewater treatment process. Biochar is a significant resource however, its application require further examination of its properties and structure and techniques to alter those factors.
Release of pollutants due to inflating anthropogenic activities has a conspicuous effect on the environment. As water is uniquely vulnerable to pollution, water pollution control has received a ...considerable attention among the most critical environmental challenges. Diverse sources such as heavy metals, dyes, pathogenic and organic compounds lead to deterioration in water quality. Demand for the pollutant free water has created a greater concern in water treatment technologies. The pollutants can be mitigated through physical, chemical and biological methodologies thereby alleviating the health and environmental effects caused. Diverse technologies for wastewater treatment with an accentuation on pre-treatment of feedstock and post treatment are concisely summed up. Pollutants present in the water can be removed by processes some of which include filtration, reverse osmosis, degasification, sedimentation, flocculation, precipitation and adsorption. Membrane separation and adsorption methodologies utilized to control water pollution and are found to be more effective than conventional methods and established recovery processes. This audit relatively features different methodologies that show remarkable power of eliminating pollutants from wastewater. This review describes recent research development on wastewater treatment and its respective benefits/applications in field scale were discussed. Finally, the difficulties in the enhancement of treatment methodologies for pragmatic commercial application are recognized and the future viewpoints are introduced.
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•Effects of water pollution are highlighted.•Major toxic pollutants and their sources and effects have been discussed.•The various pollution control technologies have been explained.•Membrane separation and adsorption processes have been highlighted.•The research gap in the treatment methods are highlighted.
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•Valorization of agro-industrial wastes has been comprehensively discussed.•Agro-industrial wastes are potential source for value creation.•Methodologies for obtaining products from ...agro-industrial wastes have been appraised.•Applications of LCA in agro-industrial circular bioeconomy have been uncovered.
Energy recovery from waste resources is a promising approach towards environmental consequences. In the prospect of environmental sustainability, utilization of agro-industrial waste residues as feedstock for biorefinery processes have gained widespread attention. In the agro-industry, various biomasses are exposed to different unit processes for offering value to various agro-industrial waste materials. Agro-industrial wastes can generate a substantial amount of valuable products such as fuels, chemicals, energy, electricity, and by-products. This paper reviews the methodologies for valorization of agro-industrial wastes and their exploitation for generation of renewable energy products. In addition, management of agro-industrial wastes and products from agro-industrial wastes have been elaborated. The waste biorefinery process using agro-industrial wastes does not only offer energy, it also offers environmentally sustainable modes, which address effective management of waste streams. This review aims to highlight the cascading use of biomass from agro-industrial wastes into the systemic approach for economic development.
Nowadays, the accumulation of toxic heavy metals in soil and water streams is considered a serious environmental problem that causes various harmful effects on plants and animals. Phytoremediation is ...an effective, green, and economical bioremediation approach by which the harmful heavy metals in the contaminated ecosystem can be detoxified and accumulated in the plant. Hyperaccumulators exude molecules called transporters that carry and translocate the heavy metals present in the soil to different plant parts. The hyperaccumulator plant genes can confine higher concentrations of toxic heavy metals in their tissues. The efficiency of phytoremediation relies on various parameters such as soil properties (pH and soil type), organic matters in soil, heavy metal type, nature of rhizosphere, characteristics of rhizosphere microflora, etc. The present review comprehensively discusses the toxicity effect of heavy metals on the environment and different phytoremediation mechanisms for the transport and accumulation of heavy metals from polluted soil. This review gave comprehensive insights into plants tolerance for the higher heavy metal concentration their responses for heavy metal accumulation and the different mechanisms involved for heavy metal tolerance. The current status and the characteristic features that need to be improved in the phytoremediation process are also reviewed in detail.
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•Recent research on remediation of toxic pollutants by biochar has been summarized.•The production techniques of the biochar have been narrated.•Biochar properties, stability and its ...environmental issues have been analysed.•Applications of biochar in soil fertility and removing pollutants have been reported.•The major stumbling block in biochar production is cost of production.
There is an upsurge enthusiasm for utilizing biochar produced from waste-biomass in different fields, to address the most important ecological issues. This review is focused on an overview of remediating harmful contaminants utilizing biochar. Production of biochar utilizing various systems has been discussed. Biochar has received the consideration of numerous analysts in building up their proficiency to remediate contaminants. Process parameters are fundamentally answerable for deciding the yield of biomass. Biochar derived from biomass is an exceptionally rich wellspring of carbon produced from biomass utilizing thermal combustion. Activating biochar is another particular region for the growing utilization of biochar for expelling specific contaminations. Closed-loop systems to produce biochar creates more opportunities. Decentralized biochar production techniques serve as an effective way of providing employment opportunities, managing wastes, increasing resource proficiency in circular bioeconomy. This paper also covers knowledge gaps and perspectives in the field of remediation of toxic pollutants using biochar.
Nanotechnology has become one of the emerging multi-disciplinary fields receiving universal attention and playing a substantial role in agriculture, environment and pharmacology. In spite of various ...techniques employed for nanoparticle synthesis such as laser ablation, mechanical milling, spinning and chemical deposition, usage of hazardous chemicals and expensiveness of the process makes it unsuitable for the continuous production. Hence the necessity of sustainable, economic and environment friendly approach development have increased in recent years. Microbial synthesis of nanoparticles connecting microbiology and nanotechnology is one of the green techniques employed for sustainable production. Gold, silver and other metal nanoparticles like platinum, palladium, molybdenum nanoparticles biosynthesis by bacteria, fungi, yeast and algae have been reported in the present review. On account of microbial rich community, several microbes have been explored for the production of nanoparticles. Nanoparticles are also employed for environmental remediation processes such as pollutant removal and detection of contaminants. Lack of monodispersity and prolonged duration of synthesis are the limitations of bio-synthesis process which can be overcome by optimization of methods of microbial cultivation and its extraction techniques. The current review describes the different microbes involved in the synthesis of nanoparticles and its environmental applications.
•Biosynthesis of metal nanoparticles by microorganisms are discussed in detail.•The review has been produced with top-down and bottom-down approaches for nanoparticle synthesis.•Current limitations and prospects of microbial nanoparticle synthesis is critically reviewed.•This review discusses on environmental applications of microbial synthesized nanoparticles.
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•Different feedstock and extraction methodologies are introduced.•Bio-derived, homo and heterogeneous catalysts for transesterification are discussed.•Mechanism of various reactors in ...biodiesel production was reviewed.•LCA involves the exploration of natural sources and ecological loads.
The deleterious condition of the ecosystem due to the extensive utilization of fossil fuels has resulted in the production of biodiesel. Currently, research is being progressed for finding out the superior catalysts for diesel production. In this review, a comprehensive summary of bio-derived catalysts in biodiesel production was presented, including feedstock, catalysts, reactors, and life cycle assessment (LCA) analysis of biodiesel production. The current status and perspectives for biodiesel production from sustainable and renewable feedstock are discussed. In addition, various extraction methodologies for biodiesel feedstock in the aspects of scalability of the process are discussed. Bio-derived catalysts are of recent interest as a potential alternative to conventional chemical catalysts owing to their low-cost, porosity, high surface area, eco-friendly and unique properties. Bio-derived materials are composed of biological and industrial waste and are a rich source of minerals such as calcium and potassium that can develop the rate of transesterification/esterification process. Various techniques have been put forward for obtaining biological active catalysts from industrial and eco-waste materials. This review focuses on the utilization of bio-based materials as catalysts for biodiesel production. Also discussed, the process occurs in a bioreactor along with process parameters such as reaction time, temperature, feedstock and catalysts concentration. For commercial and efficient production of biodiesel, it is significant to utilize a few novel methodologies that result in favorable biodiesel production. The lifecycle, environmental impact, and economic feasibility of biodiesel production have also been discussed.
The presence of pollutants and toxic contaminants in water sources makes it unfit to run through. Though various conventional techniques are on deck, development of new technologies are vital for ...wastewater treatment and recycling. Polymers have been intensively utilized recently in many industries owing to their unique characteristics. Biopolymers resembles natural alternative to synthetic polymers that can be prepared by linking the monomeric units covalently. Despite the obvious advantages of biopolymers, few reviews have been conducted. This review focuses on biopolymers and composites as suitable adsorbent material for removing pollutants present in environment. The classification of biopolymers and their composites based on the sources, methods of preparation and their potential applications are discussed in detail. Biopolymers have the potentiality of substituting conventional adsorbents due to its unique characteristics. Biopolymer based membranes and effective methods of utilization of biopolymers as suitable adsorbent materials are also briefly elaborated. The mechanism of biopolymers and their membrane-based adsorption has been briefly reviewed. In addition, the methods of regeneration and reuse of used biopolymer based adsorbents are highlighted. The comprehensive content on fate of biopolymer after adsorption is given in brief. Finally, this review concludes the future investigations in recent trends in application of biopolymer in various fields in view of eco-friendly and economic perspectives.
•Sources, structure, and preparation methods of biopolymers were reviewed.•Biopolymer based membranes for wastewater treatment are discussed.•Review focuses on biopolymer composites as adsorbents for toxic pollutant removal.•Fate of biopolymers after pollutant removal have been explained in brief.•Regeneration and reuse of spent biopolymers have also been deliberated.
Industrialization, urbanization and other anthropogenic activities releases different organic and inorganic toxic chemicals into the environment which prompted the water contamination in the ...environment. Different physical and chemical techniques have been employed to treat the contaminated wastewater, among them biological wastewater treatment using algae has been studied extensively to overwhelm the constraints related to the usually utilized wastewater treatment techniques. The presence of bacterial biota in the wastewater will form a bond with algae and act as a natural water purification system. The removal efficiency of single algae systems was very low in contrast with that of algal-bacterial systems. Heterotrophic microorganisms separate natural organic matter that is discharged by algae as dissolved organic carbon (DOC) and discharges CO2 that the algae can take up for photosynthesis. Algae bacteria associations offer an exquisite answer for tertiary and scrape medicines because of the capacity of micro-algae to exploit inorganic compounds for their development. Furthermore, for their ability to evacuate noxious contaminants, in this way, it does not prompt optional contamination. The present review contribute the outline of algae-bacteria symbiotic relationship and their applications in the wastewater treatment. The role of algae and bacteria in the wastewater treatment have been elucidated in this review. Moreover, the efforts have been imparted the importance of alage-bacteria consortium and its applications for various pollutant removal from the environment.
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•Highlighted the algae-bacteria consortium and its application in wastewater treatment.•Algae-bacteria symbiosis is a promising innovation to reduce organic pollutant in the wastewater.•Bacteria enhance energy (H2) production by algae during the treatment process.•Microbial species, BOD, COD, pH, Temperature and light supply are the major factors which affect the algal framework.
Industrialization and other human anthropogenic activities cause serious threats to the environment. The toxic pollutants can cause detrimental diseases on diverse living beings in their respective ...ecosystems. Bioremediation is one of the efficient remediation methods in which the toxic pollutants are removed from the environment by the application of microorganisms or their biologically active products (enzymes). Typically, the microorganisms in the environment produce various enzymes to immobilize and degrade the toxic environmental pollutants by utilizing them as a substrate for their growth and development. Both the bacterial and fungal enzymes can degrade the toxic pollutants present in the environment and convert them into non-toxic forms through their catalytic reaction mechanism. Hydrolases, oxidoreductases, dehalogenases, oxygenases and transferases are the major classes of microbial enzymes responsible for the degradation of most of the toxic pollutants in the environment. Recently, there are different immobilizations and genetic engineering techniques have been developed to enhance enzyme efficiency and diminish the process cost for pollutant removal. This review focused on enzymatic removal of toxic pollutants such as heavy metals, dyes, plastics and pesticides in the environment. Current trends and further expansion for efficient removal of toxic pollutants through enzymatic degradation are also reviewed in detail.
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•Enzymatic degradation of environmental pollutants is expansively reviewed.•Single microbial enzymes have better catalytic efficiency than mixed enzymes.•Bacterial enzyme dioxygenase converts the hydrophobic compounds into hydrophilic.•Toxic dyes were converted into non-toxic form through demineralization.•Enzyme efficiency enhanced by immobilization and genetic engineering approaches.
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