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Global warming in 2023 shows no signs of slowing down. The situation alarms scientists, including the Intergovernmental Panel on Climate Change, the international body responsible for regularly developing knowledge on climate change. Indeed, some impacts are already threatening the environment. Today, the average global temperature has increased by about 1 °C compared to the pre-industrial era (1850–1900). At the current rate, the increase in global average temperature will reach 1.5 °C between 2030 and 2052. The greenhouse effect is unbalanced by human activities, in particular the use of fossil fuels (oil, gas, and coal), which lead to the release of greenhouse gases. CO2 represents nearly 2/3 of global greenhouse gas emissions caused by human activities and has the tendency to linger in the atmosphere for a long time. This is why the effect of other greenhouse gases is usually measured in CO2 equivalent. Current CO2 emissions will impact atmospheric concentrations and global temperatures for decades. To date, some solutions have been proposed to deal with this (energy transition, regulation of emissions, etc.). However, most of these solutions have not yet been sufficiently developed and/or do not offset the effects of ever-increasing industrialization on anthropogenic CO2 emissions. As a result, carbon capture and sequestration processes appear to be attractive solutions. CO2 capture can take place by absorption (chemical and/or physical) and/or adsorption (chemisorption and/or physisorption). Various compounds can act as sorbents, among which polysaccharides and lignin have special importance due to their many advantages, the most important of which are biodegradability, availability, relatively cheapness, environmental friendliness, etc. In this review, we report recent studies regarding polysaccharides and lignin-based materials for CO2 capture. Such materials can be in different forms such as composites, aerogels, hydrogels, pellets, heteroatom-doped materials, membranes, metal–organic frameworks (MOFs), porous carbons, etc. These materials are used for CO2 capture through the adsorption or absorption processes. [ABSTRACT FROM AUTHOR]

The need to replace renewable polymers such as marine-based resources with non-biodegradable, plastic polymers has increased due to environmental issues. Carrageenan is a phycocolloid derived from Irish Moss or carrageenan moss, a type of red algae, mainly Chondrus crispus from which the name carrageenan is derived. Due to the wide variety of algae, they can be extracted from, there are variations in the structures of carrageenan, developed from a basic linear sulfated galactose chain. It performs diverse valuable roles through its aptitude to maintain great amounts of water, being able to form a gel at room temperature, metal chelating, and activities. Carrageenan revealed potential bioactive properties, like immunomodulatory, antiviral, antibacterial, anticoagulant, antioxidant, and antitumor actions. As mentioned, this polymer has hydrogel formation capacity, and its gelling ability is applied in various fields such as pharmaceutical sciences, food technology, biotechnology, engineering, etc. This review contains exhaustive information regarding carrageenan structures, extraction methods, the gel formation mechanism, properties, and the recent development in biomedical and environmental applications of carrageenan-based hydrogels. The biomedical applications comprise wound healing, drug delivery, and tissue engineering. In the field of environmental applications, these hydrogels are employed in the elimination of varied aqueous contaminants like dyes, drugs, metals, etc. at the end of the review, several existing challenges and prospects are also described. [ABSTRACT FROM AUTHOR]

Chromium is a potentially poisonous and carcinogenic species, which originates from human activities and various industries such as leather, steel, iron, and electroplating industries. Chromium is present in various oxidation states, among which hexavalent chromium (Cr(VI)) is highly toxic as a natural contaminant. Therefore, chromium, particularly Cr(VI), must be eliminated from the environment, soil, and water to overcome significant problems due to its accumulation in the environment. There are different approaches such as adsorption, ion exchange, photocatalytic reduction, etc. for removing Cr(VI) from the environment. By converting Cr(VI) to Cr(III), its toxicity is reduced. Cr(III) is essential for the human diet, even in small amounts. Today, biopolymers such as alginate, cellulose, gum, pectin, starch, chitin, and chitosan have received much attention for the removal of environmental pollutants. Biopolymers, particularly polysaccharides, are very useful compounds due to their OH and NH 2 functional groups and some advantages such as biodegradability, biocompatibility, and accessibility. Therefore, they can be widely applied in catalytic applications and as efficient adsorbents for the removal of toxic compounds from the environment. This review briefly investigates the application of polysaccharide-based (nano)materials for efficient Cr(VI) removal from the environment using adsorption/reduction, photocatalytic, and chemical reduction mechanisms. [Display omitted] • Polysaccharide-based (nano)materials show remarkable potential for the removal of Cr(VI). • Recent studies on the preparation of polysaccharide-based (nano)materials have been reviewed. • Catalytic removal of Cr(VI) has been presented. • Future challenges for the removal of Cr(VI) using polysaccharide-based (nano)materials have been discussed. [ABSTRACT FROM AUTHOR]

One of the most abundant wastes from all around the world is nutrient resources. Among them, fruits, their extracts, and residues comprise a major portion, which contain many valuable components that get lost during disposal or become burden on the shrinking landfills. These concerns are addressed by seeking sustainable processing methods that would have a minimal environmental impact. The crops contain renewable chemicals which are useful for catalysis, wastewater treatment, or preparation of nanomaterials; there has been an upsurge for the industrial applications of (nano)materials as their environmental and catalytic appliances is a fascinating subject to design cheaper and safer catalytic systems. Due to the excellent chemical properties of the fruit extracts, they have garnered attention as cost‐effective catalysts and support materials. This review focuses on the preparation of (nano)materials and their catalytic and environmental applications and highlights the potential appliances and industrial benefits derived from these low‐cost renewable and sustainable greener sources thus essentially converting waste into wealth. [ABSTRACT FROM AUTHOR]

The application of (bio)wastes as alternatives to expensive existing catalysts is an approach that can be used to reduce environmental pollution problems. Animal bone wastes have attracted much attention as environmentally friendly heterogeneous catalysts for chemical transformations such as transesterification, oxidation, and biofuel production, owing to the substantial availability of valuable hydroxyapatite (HAp) in their structure. Most catalysts based on bone can be prepared easily by calcination. High‐temperature calcination yields highly active catalysts. Heterogeneous catalysts prepared from these renewable sources could also simply be reused and recovered without any important loss of catalytic performance. This paper reviews past efforts and recent progress on the development of different eco‐friendly catalysts derived from bone waste and some of their catalyzed chemical transformations. However, future challenges focus on crediting the conversion of unusable wastes to valuable sources to meet global requirements © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Environmental pollution is one of the important concerns for human health. There are different types of pollutants and techniques to eliminate them from the environment. We hereby report an efficient method for the remediation of environmental contaminants through the catalytic reduction of the selected pollutants. A green method has been developed for the immobilization of copper nanoparticles on magnetic lignosulfonate (Cu NPs@Fe 3 O 4 -LS) using the aqueous extract of Filago arvensis L. as a non-toxic reducing and stabilizing agent. The characterization of the prepared Cu NPs@Fe 3 O 4 -LS was achieved by vibrating sample magnetometer (VSM), Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), high resolution TEM (HRTEM), X-ray diffraction (XRD), scanning TEM (STEM), thermogravimetry-differential thermal analysis (TG/DTA), fast Fourier transform (FFT), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron (XPS) analyses. The synthesized Cu NPs@Fe 3 O 4 -LS was applied as a magnetic and green catalyst in the reduction of congo red (CR), 4-nitrophenol (4-NP), and methylene blue (MB). The progress of the reduction reactions was monitored by UV–Vis spectroscopy. Finally, the biological properties of Cu NPs@Fe 3 O 4 -LS were investigated. The prepared catalyst demonstrated excellent catalytic efficiency in the reduction of CR, 4-NP, and MB in the presence of sodium borohydride (NaBH 4) as the reducing agent. The appropriate magnetism of Cu NPs@Fe 3 O 4 -LS made its recovery very simple. The advantages of this process include a simple reaction set-up, high and catalytic antibacterial/antioxidant activities, short reaction time, environmentally friendliness, high stability, and easy separation of the catalyst. In addition, the prepared Cu NPs@Fe 3 O 4 -LS could be reused for four cycles with no significant decline in performance. [Display omitted] • Facile synthesis of magnetic lignosulfonate supported copper nanoparticles. • Efficient reduction of MB, CR and 4-NP using Cu NPs@Fe 3 O 4 -LS catalyst. • Characterization of catalyst by FTIR, XRD, VSM, (HR)TEM, TG/DTA, EDS and XPS. • The catalyst can be reused at least four times with low loss of catalytic ability. • The antibacterial/antioxidant activities of Cu NPs@Fe 3 O 4 -LS were investigated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Facile synthesis of Pd NPs through laser ablation in liquid. • Synthesis of Pd NPs supported on the on kraft lignin/TiO 2 nanocomposite. • Structural verification of the nanocatalyst by XRD, FTIR, BET, SEM, EDX, and TEM analyses. • Catalytic performances of KL-T/Pd in the MB and MO reduction in water. • Nanocatalyst can be recovered and reused four times without any notable decreasing in its catalytic performance. The evaluation of dye degradation was adorned a great interest due to scarcity of water, courtesy of industrialization. Here, Kraft lignin was upgraded by immobilization of TiO 2 nanoparticles (NPs) by the reflux method (KL-T). Palladium (Pd) NPs were produced in a promising way by laser ablation in liquid (LAL) and loaded on KL-T to prepare an efficient nanocatalyst (KL-T/Pd). The synthesized KL-T/Pd is characterized by X-ray diffraction (XRD), Fourier transforms infrared (FT-IR), Scanning electron microscopy (SEM), Energy-dispersive X-ray spectrometry (EDX), and Transmission electron microscope (TEM) analyses. The KL-T/Pd nanocomposite was applied as an efficient and novel nanocatalyst for the reduction of methylene blue (MB) and methyl orange (MO) by NaBH 4 as a reducing agent in aqueous media at ambient temperature. Our experimental results displayed that the 1 mg of KL-T/Pd catalyst can be reduced MB and MO organic dyes within 23 and 8 s, respectively at room temperature. The KL-T/Pd nanocatalyst can be recycled and reused four times with no considerable loss of performance. Having different advantages such as high catalytic performance, safe synthesis method, and high stability, lignin was suggested as a natural substrate. [ABSTRACT FROM AUTHOR]

• Recent advances in tetrazole-based catalysts are described. • Environmental and catalytic applications of tetrazole-based (nano)materials have been presented. • Stability and catalytic properties of tetrazole-based (nano)materials are highlighted. • Future challenges on tetrazole-based (nano)materials are discussed. Increasing interest in tetrazoles and tetrazole based materials in the recent century has been followed by enormous research efforts devoted for the synthesis of various kinds of materials based on these five membered heterocyclic compounds, which basically contain four nitrogen atoms. The structure of tetrazoles and their derivatives are crucial in preparing complexes since they can act as ligands to modify the reactivity and selectivity of the metal centers in the catalyst and prepare energetic materials. The wide field of tetrazole applications as efficient, air stable and inexpensive materials has drawn attention to the methods to synthesize various kinds of tetrazoles and their derivatives. This study primarily focuses on the fabrication methods of tetrazoles and preparation of tetrazole based compounds and their utilizations in environmental, catalytic, and energetic applications. The significant applications of tetrazole, as a catalyst, energetic material and efficient ligand in the organic catalysis or formation of various catalysts are described with an emphasis on its performance, reusability and stability and environmental concerns such as treatment of wastewater and water. Finally, a brief summary and an outlook on some of the scientific challenges and opportunities of these materials have also been discussed. [Display omitted] [ABSTRACT FROM AUTHOR]

Heck cross-coupling reaction (HCR) is one of the few transition metal catalyzed C C bond-forming reactions, which has been considered as the most effective, direct, and atom economical synthetic method using various catalytic systems. Heck reaction is widely employed in numerous syntheses including preparation of pharmaceutical and biologically active compounds, agrochemicals, natural products, fine chemicals, etc. Commonly, Pd-based catalysts have been used in HCR. In recent decades, the application of biopolymers as natural and effective supports has received attention due to their being cost effective, abundance, and non-toxicity. In fact, recent studies demonstrated that biopolymer-based catalysts had high sorption capacities, chelating activities, versatility, and stability, which make them potentially applicable as green materials (supports) in HCR. These catalytic systems present high stability and recyclability after several cycles of reaction. This review aims at providing an overview of the current progresses made towards the application of various polysaccharide and gelatin-supported metal catalysts in HCR in recent years. Natural polymers such as starch, gum, pectin, chitin, chitosan, cellulose, alginate and gelatin have been used as natural supports for metal-based catalysts in HCR. Diverse aspects of the reactions, different methods of preparation and application of polysaccharide and gelatin-based catalysts and their reusability have been reviewed. Current trends, challenges and future prospects exploiting the sustainable applications of chitin, chitosan, starch, cellulose, pectin, alginate, gelatin and gum based (nano)catalysts for the Heck coupling reactions, are highlighted. [Display omitted] • Advances in Heck coupling reactions by biopolymer-based catalysts are described. • Synthetic methods for attaining biopolymer-based catalysts are highlighted. • Catalytic activity of chitin, chitosan, starch, cellulose, pectin, alginate, gelatin and gum based catalysts are presented. • Mechanistic details are provided for Heck coupling reactions using biopolymer-based catalysts. • Future challenges pertaining to Heck coupling reactions using biopolymer-based catalysts are discussed. [ABSTRACT FROM AUTHOR]

Over the course of a few decades, the concern of environmental damages of fossil fuels, an increase in CO 2 emission and a decrease of hydrogen have been growing more and more. Accordingly, hydrogen production is a crucial issue nowadays. Different polymers are applied to attain the purpose. Among all polymers, biodegradables polymers are the best choices to develop the main aim. Polysaccharides and proteins are biodegradable polymers with unique places and advantages with regards to their ecofriendly properties. There are different techniques to apply and achieve the foremost purpose. It is worthwhile to mention that green and facile methods are always attracting attention in different aspects and fields. The three non-polluting and economical techniques, that is, electrochemical hydrogen evolution reaction (HER), photocatalytic technique, and hydrolysis of hydrides, are reviewed in this paper. This review helps researchers, who are environment supporters, to evaluate and choose the most ecological biopolymers and processes in their work. [Display omitted] • Developments in hydrogen evolution by biopolymer-derived (nano)catalysts have been described. • Summary of synthetic procedures to obtain biopolymer-derived (nano)catalysts. • Future challenges of hydrogen evolution using biopolymer-derived (nano)catalysts have been discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Advances in oxidation reactions by lignin derived (nano)catalysts, are described. • Summary of synthetic methods for attaining lignin derived (nano)catalysts. • Catalytic oxidation of alcohols, phenols, etc, are presented. • Mechanistic details are provided for oxidation with lignin derived (nano)catalysts. • Future challenges on oxidation reactions using lignin derived (nano)catalysts are discussed. Recently, the attention to bio-based catalysts has been on rise. The present review explains the developments regarding preparation, characterization and utilization of lignin based (nano)catalysts in oxidation reactions. Herein, the application of lignin in the preparation of (nano)catalysts and their catalytic prowess in oxidative transformations will be overviewed. Lignin offers exceptional physicochemical characteristics and important potential applications. Lignin can be used as a precursor or template to prepare novel eco-friendly catalysts. This review paper proposes the rational design of active, economical, recyclable and efficient catalysts for different oxidation reactions including oxidation of alcohols, phenols, etc. [ABSTRACT FROM AUTHOR]

[Display omitted] • Advances in hydrogenation by polymer-supported palladium complexes, are described. • Synthetic methods are highlighted for attaining polymer-supported palladium complexes. • Catalytic hydrogenation of carbonyl- and nitro-compounds, alkynes, and alkenes, are presented. • Mechanistic details are provided for hydrogenation with polymer-supported Pd catalysts. • Future challenges pertaining to hydrogenation reactions using Pd catalysts, are discussed. Hydrogenation reactions are useful pathways and comprise an integral operation to generate valuable organic compounds. Hydrogenation reactions not only provide an effective route for the preparation of organic compounds such as amines, alkenes, alkanes, alcohols, etc. but also a significant technique to degrade environmental pollutants; reactions are often catalyzed by palladium (Pd) complexes supported on the surface of the polymers, viz. organic or non-organic and are widely deployed owing to their high efficiency, recyclability and good selectivity. Herein, an overview is presented on current developments for the generation of different classes of polymer supported palladium complexes, their characterization and application in hydrogenation of assorted compounds comprising double bonds such as carbonyl- and nitro-compounds, alkynes, and alkenes. The literature from 1981 onwards is summarized pertaining to the hydrogenation reactions deploying polymer-supported Pd complexes catalysts under diverse conditions with special emphasis on the distinguished role of polymers as support in the structural and morphological features of the ensuing catalysts. [ABSTRACT FROM AUTHOR]