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The concept of green chemistry has attracted attention due to the green synthesis and ecofriendly nature of the compounds leading to the green and sustainable chemical industries and processes. Chitosan is an ecofriendly material, which is biodegradable, non-toxic, and biocompatible. It has the potential to be modified into biofilms for various applications such as biomedical, packaging, and pharmaceutical fields. Nevertheless, some poor properties of chitosan restrict its wide applications. The incorporation of nanocellulose fillers into chitosan matrix can enhance the mechanical and thermal properties of chitosan. Cellulose nanomaterials can be achieved through chemical and mechanical modifications. The common type of nanocellulose are cellulose nanofibers (CNFs), cellulose nano-whiskers (CNWs), tunicate CNCs (t-CNCs), algae cellulose particles (AC) and bacterial cellulose particles (BC). Nanocellulose are applied as the reinforcement fillers in various polymer matrices such as polysaccharides, proteins, lipids, polylactic acid etc. Deep eutectic solvents (DES) are relatively novel green solvents, which can be applied in various fields. DES are widely applied in metal processing, polymer processing and synthesis. Even though there are not much studies available on DES for synthesis of nanocomposite films; however they are used as eco-friendly solvents in manufacturing processes. This study reviews the discovery, structure, properties of chitosan and cellulose, their derivatives and applications. In addition, the paper also discusses the properties of DES and their applications.

The demand for the development of high-performance and eco-friendly nanocomposites is soaring up. This is because of their desired mechanical, thermal, electrical, magnetic, catalytic, and optical properties and their ecofriendly development. The diversity of nanocomposites has introduced them to a wide variety of applications such as drug delivery, biosensors, bone regeneration, solar cells, super capacitors, fuel cells, automobiles etc. The nanocomposites are deemed competing materials for the sustainable development, this is because of their ecofriendly behavior and value addition. This manuscript reviews the status of the silicon enhanced nanocomposites, various classes of nanocomposites such as ceramic based matrix nanocomposites, metal-based matrix nanocomposites, Polymer based matrix nanocomposites, etc. advanced green polymer-based nanocomposites and sustainable nanofillers for nanocomposites. The applications of nanocomposites in various sectors such as energy, automobiles, packaging, biomedical, environment and safety have been critically reviewed.

Synthesis of hybrid nanomaterials in the lab-scale frequently involves complex processing and often is not able to be adopted in the industry without major enhancements for its commercial production. This research is focused on a convenient route for the fabrication of chitosan-supported magnetically recoverable carbon bio-nanocomposites by functionalizing magnetic nanoparticles on chitosan and renewable carbon material using solvothermal carbonization co-precipitation (STCC). This process can be adopted in large-scale synthesis with minimum enhancements. The nanocomposites produced using STCC offered excellent features including porous and ultrafine nanostructure, stable mechanical, and chemical properties. From the analysis of variance (ANOVA), the temperature has been found to be the most influential factor for both magnetic nanocomposite and bio-oil yield. The highest porosity for nanocomposites was observed with water-based synthesis at 260 °C at 194.62 m2/g. However, water/ethanol (50:50) at 260 °C yielded 6.67% and 8.01% more bio-oil and having 5.35% and 3.49% higher heating value as compared to that of bio-oil produced using water and ethanol.

Emerging pollutants (EPs) in the environment have become a significant source of pollution and cause of serious concern for the ecosystem and human health. Although during the recent decades, extensive research has been performed worldwide for the detection and analysis of EPs, continuous refinement, and development of specific analytical techniques; a great number of undetected EPs still need to be investigated in different components of the ecosystem and biological tissues. Therefore, this chapter provides extensive reviews of several emerging pollutants reported around the globe along with their physiochemical properties and potential ecological impacts. Moreover, formulated legislations and policy regulations for the monitoring of EPs are also discussed in this chapter.

Oil spills are a major contributor to water contamination, which sets off a significant impact on the environment, biodiversity, and economy. Efficient removal of oil spills is needed for the protection of marine species as well as the environment. Conventional approaches are not efficient enough for oil-water separation; therefore, effective strategies and efficient removal techniques (and materials) must be developed to restore the contaminated marine to its normal ecology. Several research studies have shown that nanotechnology provides efficient features to clean up these oil spills from the water using magnetic nanomaterials, particularly carbon/polymer-based magnetic nanocomposites. Surface modification of these nanomaterials via different techniques render them with salient innovative features. The present review discusses the advantages and limitations of conventional and advanced techniques for the oil spills removal from wastewater. Furthermore, the synthesis of magnetic nanocomposites, their utilization in oil-water separation, and adsorption mechanisms are discussed. Finally, the advancement and future perspectives of magnetic nanocomposites (particularly of carbon and polymer-based magnetic nanocomposites) in environmental remediation are presented.

Compared with traditional battery and super capacitor materials, nanomaterials can significantly improve ion transport and electron conductivity. There are many features to the achievement of nanomaterials in energy storage applications. Nanomaterials development and their related processes can improve the performance based on the energy storage existing system. Current study discuss fruitful approaches and outline a roadmap for using green nanomaterials for advancement in energy storage devise. This review includes the information of the latest research being carried out on green nanomaterials and its sustainability. It also provides an overview of the latest state and proposes the future direction of the use of green nanomaterials for numerous possible applications, which are mainly used in the fields of biotechnology, agriculture, and biomedicine.

Aerogel is a special type of porous material with many outstanding physical and chemical properties, such as low density, high porosity, high surface area, and adjustable surface chemistry. Thanks to the latest advances in the synthesis of different types of aerogels, the feasibility of this porous material in several applications has been widely explored. In a variety of high performance applications, aerogels have received much attention as an adsorption medium that removes a variety of environmental and human health pollutants. Although the performance of aerogels in environmental sanitation is encouraging, some shortcomings of aerogels, such as complex drying process, mechanically fragile structure and processing costs, have also been taken into account and have been taken into account been determined in some studies. Degree of relief. This review article aims to describe the synthesis and processing of aerogels and their latest applications in air purification, such as carbon dioxide capture and VOC removal, as well as applications in the treatment of air, water, including oils and toxic organic compounds and heavy metals ion removal.

The objective of this study is the applications of hybrid magnetic nanocomposites as catalyst as well as an adsorbent. Four magnetic nanocomposites (graphene and chitosan based) were fabricated using single pot solvothermal carbonization co-precipitation (STCC) route by integrating biomass functionalized with iron oxide nanoparticles. All hybrid nanocomposites were characterized for their magnetic, thermal, chemical and structural properties. Adsorption isotherms and kinetics studies were performed for adsorption of multi-heavy metals including Cd, Ni, Cu and Cr. Finally, the hybrid magnetic carbon nanocomposites were tested as catalysts to produce bio-oil through catalytic liquefaction of rice husk in supercritical ethanol. It was found that the bio-oil yield and overall conversion was enhanced significantly from 29.5% and 48.11% without catalyst, to 36.8% and 60.81% respectively with the presence of magnetic carbon nanocomposites as catalyst. Furthermore, the bio-oil energy quality was enhanced in energy content from 21.72 to 23.21 MJ/kg with the presence of catalyst and H/C and O/C ratios were reduced. Finally, GCMS revealed that the bio-oil produced using catalysts showed higher mass fraction of esters, hydrocarbons and reduced acid groups as compared to bio-oil. This study provides insights to the understanding of the role of hybrid magnetic nanocomposites for its expansion for future applications.

This work presents a review of nanocomposites of nickel oxides (NiO, nickel cobaltite NiCo2O4), nickel hydroxides (Ni(OH)2), layered-double hydroxides of Ni (LDH-Ni) with graphene, functionalized-g...

Water consumption has grown in recent years due to rising urbanization and industry. As a result, global water stocks are steadily depleting. As a result, it is critical to seek strategies for removing harmful elements from wastewater once it has been cleaned. In recent years, many studies have been conducted to develop new materials and innovative pathways for water purification and environmental remediation. Due to low energy consumption, low operating cost, and integrated facilities, membrane separation has gained significant attention as a potential technique for water treatment. In these directions, MXene which is the advanced 2D material has been explored and many applications were reported. However, research on MXene-based membranes is still in its early stages and reported applications are scatter. This review provides a broad overview of MXenes and their perspectives, including their synthesis, surface chemistry, interlayer tuning, membrane construction, and uses for water purification. Application of MXene based membrane for extracting pollutants such as heavy metals, organic contaminants, and radionuclides from the aqueous water bodies were briefly discussed. Furthermore, the performance of MXene-based separation membranes is compared to that of other nano-based membranes, and outcomes are very promising. In order to shed more light on the advancement of MXene-based membranes and their operational separation applications, significant advances in the fabrication of MXene-based membranes is also encapsulated. Finally, future prospects of MXene-based materials for diverse applications were discussed.

Multiple ecological contaminants in gaseous, liquid, and solid forms are vented into ecosystems due to the huge growth of industrialization, which is today at the forefront of worldwide attention. High-efficiency removal of these environmental pollutants is a must because of the potential harm to public health and biodiversity. The alarming concern has led to the synthesis of improved nanomaterials for removing pollutants. A path to innovative methods for identifying and preventing several obnoxious, hazardous contaminants from entering the environment is grabbing attention. Various applications in diverse industries are seen as a potential avenue for researchers. MXene is a new, excellent, and advanced material that has received much environmental attention. Due to its unique physicochemical and mechanical properties, high specific surface area, physiological compatibility, strong electrodynamics, and raised specific surface area wettability, its applications are growing. This review paper examines the most recent methods and trends for environmental pollutant removal using advanced 2D Mxene materials. In addition, the history and the development of MXene synthesis were elaborated. Furthermore, an Extreme summary of various environmental pollutants removal has been discussed, and the future challenges and perspectives have been illustrated.

Abundant CO2 emissions from industries and the transportation sector cause an alarming threat to the planet due to overwhelming concerns over CO2 induced climate change. To resolve this tremendous environmental pollution, the long-term solution for CO2 mitigation exists in the conversion of CO2 into value-added products through catalysis. Among several catalysts, metal organic frameworks (MOFs) are one of the remarkable candidates for CO2 conversion into fuels and chemicals. The MOFs are molded with robust structures, high porosity, high potential of CO2 adsorption, maximum atom utilization due to high dispersion and isolation of active sites of MOFs, tunability of the metal nodes, organic ligands, etc. MOFs have been implemented for several CO2 conversion processes such as cycloaddition of CO2 to epoxides, photocatalytic CO2 reduction, electrocatalytic CO2 reduction, hydrogenation, and others. These processes convert CO2 into products like cyclic carbonates, alkyl formate, formic acid, ethanol, methanol, methane, CO, and others. This study strived to explain elaborately the formation of fuels and chemicals through different catalytic processes using MOFs. Detailed reaction conditions, catalyst chemistry, reaction mechanisms, and formation rates for alkyl formate, formic acid, methanol, ethanol, CO, and methane have been critically analyzed in present study.

Hydrothermal carbonization (HTC) and its parameters show a significant role in the quality of HTC products and the distribution of yield. The present study investigates the optimal conditions that are suitable to produce maximum yield products of solid, liquid, and gas, from HTC of oil palm trunk (OPT), by following the Taguchi method. Moreover, all the three products of HTC were analyzed using various characterizations. The optimum runs for hydrochar yield, liquid yield, and gaseous yield were run 1 (R1), run 4 (R4), and run 9 (R9), respectively. The reaction temperature was found to be the most influential parameter that affected the yield distribution during HTC, where low temperature supported solid production, intermediate temperatures favored liquid yield, and high temperature produced higher gaseous yield. Elemental analysis, H/C and O/C atomic ratios, higher heating value (HHV), and energy density values of hydrochar recommended that the HTC process has significantly converted OPT into better energy fuel. The energy densification value of hydrochar ranged between 1.28 and 1.40, which confirmed the significance of the HTC process. Two characteristic peaks from FTIR were observed at 3,430 cm−1 and 2,923 cm−1 hydrochar. SEM analysis confirmed that the porosity of hydrochar was higher than OPT after HTC. However, the major organic matter in the bio-oil traced by GC-MS analysis was acetic acid, accounting for about 59.9–71.7%, and the outlet gaseous product consisted of 0.87–9.17% CH4, 3.88–29.02% CO2, 1.07–7.89% CO, and 0.31–1.97% H2, respectively, as shown by GC-TCD.

Recent years have witnessed rise in the production of microbial fermentation of metabolites and proteins for industrial applications. The innovative method aims to improve the conventional batch fermentation and the separation. Furthermore, the idea of downstream processing of the target product enhances the efficiency of the overall process and makes it cost-effective and eco-friendly. Even though being cost-effective and eco-friendly, the process faces challenges in commercial applications. When the concentration of the final product/by-product reaches a certain level, feedback inhibition is a common problem encountered in the fermentation process. Excessive accumulation of end products/by-products in culture also inhibits cell growth and secretion of target metabolites. The fermentation results in the production of antibiotics, fungal metabolites, and amino acids, which come with serious inhibition problems. Hence, to mitigate such problems and enhance fermentation performance, extractive fermentation via in situ ion exchange adsorptive technique can be incorporated. The present review highlights the advances and suggests the strategies to resolve the inhibition problems using extractive fermentation via internal, external, and dispersed resin systems. Furthermore, methods for synthesis of resins are discussed and adsorption mechanism of ion exchanges is also elaborated.

Numerous contaminants in huge amounts are discharged to the environment from various anthropogenic activities. Waterbodies are one of the major receivers of these contaminants. The contaminated water can pose serious threats to humans and animals, by distrubing the ecosystem. In treating the contaminated water, adsorption processes have attained significant maturity due to lower cost, easy operation and environmental friendliness. The adsorption process uses various adsorbent materials and some of emerging adsorbent materials include carbon- and polymer-based magnetic nanocomposites. These hybrid magnetic nanocomposites have attained extensive applications in water treatment technologies due to their magnetic properties as well as combination of unique characteristics of organic and inorganic elements. Carbon- and polymer-related magnetic nanocomposites are more adapted materials for the removal of various kinds of contaminants from waterbodies. These nanocomposites can be produced via different approaches such as filling, pulse-laser irradiation, ball milling, and electro-spinning. This comprehensive review is compiled by reviewing published work of last the latest recent 3 years. The review article extensively focuses on different approaches for producing various carbon- and polymer-based magnetic nanocomposites, their merits and demerits and applications for sustainable water purification. More specifically, use of carbon- and polymer-based magnetic nanocomposites for removal of heavy metal ions and dyes is discussed in detail, critically analyzed and compared with other technologies. In addition, commercial viability in terms of regeneration of adsorbents is also reviewed. Furthermore, the future challenges and prospects in employing magnetic nanocomposites for contaminant removal from various water sources are presented.

Degradation of amines is a significant issue allied to amine-based carbon dioxide (CO2) absorption in post-combustion CO2 capture. It becomes essential to have a detailed understanding of degradation products for advanced post-combustion CO2 capture technology. Identification and quantification of degradation products of amines help in practicability and environmental assessment of amine-based technology. Gas, liquid, and ion chromatographic techniques are the benchmark tools for qualitative and quantitative analyses of the amines and their derivatives. Among others, gas chromatography has been more in use for this specific application, especially for the identification of degradation products of amines. This review focuses on the critical elucidation of gas chromatographic analysis and development of methods to determine the amine degradation products, highlighting preparation methods for samples and selecting columns and detectors. The choice of detector, column, sample preparation, and method development are reviewed in this manuscript, keeping in view the industry and research applications. Furthermore, obtained results on the quantitative and qualitative analyses using gas chromatography are summarized with future perspectives.

This study aims to investigate the co-liquefaction of high-density polyethylene (PE) and low density polyethylene bags (PB) with sugarcane bagasse (SCB) in supercritical ethanol solvent. The effect of blending ratios of SCB/PB and SCB/PE is studied. Results indicate that blending ratio of low density plastic bags and high-density polyethylene impacts the product distribution during solvo-thermal process. The optimum conversion of SCB/PE and SCB/PB up to 57.3% and 59.4% with bio-oil yields of 31.5% and 30.3% respectively are obtained at 280 °C. The higher heating values (HHV) of bio-oil obtained from SCB/PE and SCB/PB are 34.9 and 34.8 MJ/kg, respectively. CHNS/O, chemical composition, carbon and proton NMR, Thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR) analyses of bio-oil have been conducted. Investigation suggests that the SCB/PE and SCB/PB derived bio-oil have the superior qualitative properties compared to pure sugarcane bagasse.

Indigenous hematite iron ore was chemically activated as a function of various hydrogen peroxide concentrations (0.5, 1, 1.5, and 2.0 M), activation time, and iron ore size. Adsorption potential was evaluated at various initial arsenic concentrations, contact time, adsorbent dose, and particle size. Maximum 95% removal efficiency was achieved at 600-μm size of iron ore, activated with 0.5 M concentration of hydrogen peroxide at 24 h of activation time. The experimental data were further evaluated through Langmuir and Freundlich isotherms. The maximum 14.46 mg/g of adsorption capacity was observed through Langmuir isotherm. Moreover, adsorption kinetics was evaluated using pseudo-first-order and pseudo-second-order kinetics, and the intra-particle diffusion model. The kinetics of arsenic adsorption was best described by using the pseudo-first-order kinetics with a kinetic rate of 0.621 min−1. The hematite iron ore before and after arsenic adsorption was characterized by XRD, SEM, and EDX.

Substantial discharge of hazardous substances, especially dyes and heavy metal ions to the environment, has become a global concern due to many industries neglecting the environmental protocols in waste management. A massive discharge of contaminantsfrom different anthropogenic activities, can pose alarming threats to living species and adverse effect to the ecosystem stability. In the process of treating the polluted water, various methods and materials are used. Hybrid nanocomposites have attained numerous interest due to the combination of remarkable features of the organic and inorganic elements in a single material. In this regards, carbon and polymer based nanocomposites have gained particular interest because of their tremendous magnetic properties and stability. These nanocomposites can be fabricated using several approaches that include filling, template, hydrothermal, pulsed-laser irradiation, electro-spinning, detonation induced reaction, pyrolysis, ball milling, melt-blending, and many more. Moreover, carbon-based and polymer-based magnetic nanocomposites have been utilized for an extensive number of applications such as removal of heavy metal and dye adsorbents, magnetic resonance imaging, and drug delivery. This review emphasized mainly on the production of magnetic carbon and polymer nanocomposites employing various approaches and their applications in water and wastewater treatment. Furthermore, the future opportunities and challenges in applying magnetic nanocomposites for heavy metal ion and dye removal from water and wastewater treatment plant.

A mechanistic model is developed to investigate the influence of an activator on the corrosion rate of carbon steel in the absorption processes of carbon dioxide (CO2). Piperazine (PZ) is used as an activator in diethanolamine (DEA) aqueous solutions. The developed model for corrosion takes into consideration the effect of fluid flow, transfer of charge and diffusion of oxidizing agents and operating parameters like temperature, activator concentration, CO2 loading and pH. The study consists of two major models: Vapor–liquid Equilibrium (VLE) model and electrochemical corrosion model. The electrolyte-NRTL equilibrium model was used for determination of concentration of chemical species in the bulk solution. The results of speciation were subsequently used for producing polarization curves and predicting the rate of corrosion occurring at the surface of metal. Results of corrosion rate for the mixtures of activated DEA showed an increase in concentration of activator increases rate of corrosion of carbon steel.

The ever-increasing CO2 emission has necessitated the search for suitable technologies for CO2 utilization at a low cost. Recently, a novel concept called reactive gas electrosorption (RGE) for energy harvesting from CO2 emission, which could boost the efficiency of a thermal power plant by 5% was proposed by Hamelers and coworkers. The concept involves mixing of air stream with a low CO2 concentration with a stream of high CO2 concentration in an alkaline aqueous electrolyte. However, this concept is faced with the challenges of designs specific for CO2-electrolyte, and inadequate performance of the electrode materials. Therefore, this study showcases electricity generation opportunities from CO2 via RGE and discussed challenges and prospect. The study reveals that the drawback relating to the electrode could be solved using heteroatom doped traditional carbon materials and composite carbon-based materials, which has been successfully used in capacitive cells designed for desalination. This modification helps to improve the hydrophilicity, thereby improving electrode wettability, and suppressing faradaic reaction and co-ion repulsion effect. This improvement could enhance the charge efficiency, sorption capacity durability of electrodes and reduce the energy loss in RGE. Moreover, intensification of the membrane capacitive deionization (MCDI) process to obtain variances like enhanced MCDI and Faradaic MCDI. Hybrid capacitive deionization (HCDI) is also a promising approach for improvement of the capacitive cell design in RGE. This intensification can improve the electrosorption capacity and minimize the negative effect of faradaic reaction. The use of alternative amine like Piperazine, which is less susceptible to degradation to boosting CO2 dissolution is also suggested.

Photo-Fenton oxidation is one of the most promising processes to remove recalcitrant contaminants from industrial wastewater. In this study, we developed a novel heterogeneous catalyst to enhance photo-Fenton oxidation. Multi-composition (Fe-Cu-Zn) on aluminosilicate zeolite (ZSM-5) was prepared using a chemical process. Subsequently, the synthesized catalyst was characterized by using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (spectroscopy) (EDX), and Brunauer-Emmett-Teller (BET). Activity of the synthesized catalyst is analysed to degrade an azo dye, methyl orange. Taguchi method is used to optimize color removal and total carbon content (TOC) removal. The dye completely degraded, and 76% of TOC removal was obtained at optimized process conditions. The amount of catalyst required for the desired degradation of dye significantly reduced up to 92% and 30% compared to conventional homogenous and heterogeneous Fenton oxidation processes, respectively.

Due to the rapid growth in the heavy metal-based industries, their effluent and local dumping have created significant environmental issues. In the past, typically, removal of heavy metals was handled by reverse osmosis and ion exchange techniques, but these methods have many disadvantages. Therefore, extensive work into the development of improved techniques has increased, especially for heavy metal removal. Many countries are currently researching new materials and techniques based on nanotechnology for various applications that involve extracting heavy metals from different water sources such as wastewater, groundwater, drinking water and surface water. Nanotechnology provides the possibility of enhancing existing techniques to tackle problems more efficiently. The development in nanotechnology has led to the discovery of many new materials such as magnetic nanoparticles. These nanoparticles demonstrate excellent properties such as surface-volume ratio, higher surface area, low toxicity and easy separation. Besides, magnetic nanoparticles can be easily and efficiently recovered after adsorption compared with other typical adsorbents. This review mainly emphasises on the efficiency of heavy metal removal using magnetic nanoadsorbent from aqueous solution. In addition, an in-depth analysis of the synthesis, characterisation and modification approaches of magnetic nanoparticles is systematically presented. Furthermore, future opportunities and challenges of using magnetic particles as an adsorbent for the removal of heavy metals are also discussed.

The extraction of concentrated volatile oils from various plant species is generally carried out by hydrodistillation technique. However, this hydrodistillation technique is expensive owing to more solvent and energy consumption. In this study, effect of ultrasonic pre-treatment prior to hydrodistillation on extraction of Cinnamomum cassia bark oil was evaluated. Process variables for extraction were optimized by Taguchi method. Results revealed that ultrasound pre-treatment hydrodistillation (UAHD) can enhance the yield of the extracted oil when compared with conventional hydrodistillation (HD) technique. To predict the yield of the extracted essential oil significant mathematical model was developed. Optimum parameters were determined according to the mathematical model they were: solid loading 25 g, ultrasound power 600 W, extraction time 35 min, and solvent quantity 100 ml. Further, gas chromatography–mass spectrometry (GC–MS) results of C. cassia bark oil revealed that UAHD produced more oxygenated compounds than HD extraction method. In addition, UAHD was found to be less energy consuming and environmentally safer than HD extraction method. Moreover, FT-IR spectra indicate that the effect of UAHD extraction method released all the volatile compounds from treated C. cassia bark powder. Finally, the optimum parameters were confirmed by the experiments performed, in which the yield of the oil of 3.17% was obtained. This study demonstrated that ultrasound pre-treatment prior to hydrodistillation could be useful to extract bioactive compounds with reduction in extraction time for extraction of C. cassia bark oil.