Environmental Pollution Remediation Research Articles

Exploring the potential of eco-friendly carbon dots in monitoring and remediation of environmental pollutants.

Photoluminescent carbon dots (CDs) have garnered significant interest owing to their distinctive optical and electronic properties. In contrast to semiconductor quantum dots, which incorporated toxic elements in their composition, CDs have emerged as a promising alternative, rendering them suitable for both environmental and biological applications. CDs exhibit astonishing features, including photoluminescence, charge transfer, quantum confinement effect, and biocompatibility. Recently, CDs derived from green sources have drawn a lot of attention due to their strong photostability, reduced toxicity, better biocompatibility, enhanced fluorescence, and simplicity. These attributes have shown great promise in the areas of LED technology, bioimaging, photocatalysis, drug delivery, biosensing, and antibacterial activity. In contrast, this review offers a comprehensive overview of various green sources utilized to produce CDs and methodologies, along with their merits and demerits, with a notable emphasis on physiochemical properties. Additionally, the paper provides insight into the bibliometric analysis and recent advancements of CDs in sensing, photocatalysis, and antibacterial activity. In this field, extensive research is underway, and a total of 7,438 articles have been identified. Among these, 4242 articles are dedicated to sensing applications, while 1518 and 1678 focus on adsorption and degradation. Carbon dots demonstrate exceptional sensing capabilities within the nanomolar range with a selectivity of up to 95% for pollutants. They exhibit excellent degradation efficiency exceeding 90% within 10-130 min and possess an adsorption capacity from 100 to 800 mg/g. These fascinating qualities render them suitable for diverse applications.

Electrochemistry of 2D-materials for the remediation of environmental pollutants and alternative energy storage/conversion materials and devices, a comprehensive review

This review article explores into the complicated relationship between electrochemistry and 2D materials, exploring their mutual influences and the consequential advancements in energy conversion, storage, and environmental applications. Electrochemical reactions, manifested through oxidations and reductions at submerged electrodes, form the linchpin connecting the electrochemistry of 2D materials with their practical utility. Various electrochemical cell topologies are investigated for their role in enhancing material flexibility, operational states, energy conversion efficiency, and device design adaptability. The comprehensive discussion extends to diverse applications, emphasizing the pivotal roles of 2D materials in environmental remediation, alternate energy storage and conversion, and chemical reactivity. Noteworthy applications include pollutant detection, adsorption and absorption of pollutants, elimination of both organic and inorganic pollutants, and photocatalytic degradation. The review also addresses materials synthesis via electrochemical processes, detailing functionalization, handling, and deposition techniques. Particular focus is directed towards local electrochemical techniques enabling the analysis and local alteration of 2D materials. Moreover, this paper concludes the article published in the recent years with this topic and most significant trends observed in 2022 and 2023 with electrochemistry of materials for the remediation of environmental pollutants. While the trends of article publishing increased from 2020 to 2023 with topic alternative energy storage/conversion materials. Finally, offering a comprehensive overview of the synergistic relationship between electrochemistry and 2D materials and their transformative potential in sustainable technologies. Broader contextThe decreasing availability of energy resources and the contamination of the environment are two significant worldwide concerns that need immediate attention. The focus on 2D materials and associated technologies is important for the efficient conversion of solar energy into chemical energy. These materials have diverse applications in fields such as energy (e.g., water splitting), synthesis (e.g., production of valuable chemicals and N2 reduction), and the environment (e.g., CO2 reduction and environmental remediation). Furthermore, Electrochemical energy storage and conversion (EESC) technologies are widely acknowledged as the most viable solutions to address the escalating energy crisis and environmental degradation because to their exceptional energy efficiency and little environmental footprint. Currently, there have been several reports discussing the use of 2D-materials in energy applications and wastewater treatment. However, there is a lack of comprehensive reviews that summarize the electrochemistry of 2D-materials, their preparation strategies, modification techniques, and related properties. Furthermore, there is a need for detailed analysis of the progress in applying 2D-materials for environmental pollution remediation, electrocatalytic performance, energy storage, and conversion technologies and devices. In this paper, we systematically and comprehensively review the electrochemistry of 2D-materials and innovatively analyze the design principles and difficulties of 2D-materials. We discussed comprehensively the remediation of environmental pollutants through 2D-materials in water treatment fields such as photocatylsts, adsorption/absorption and dyes removal as an entry point and provide an in-depth knowledge and outlook on the current status and development potential of specific applications of energy storage and conversion materials and devices.

Porosity and pore structure evolution during the weathering of black shale

Pore type and pore structure evolves systematically across continuous black shale weathering profile. However, the extend and process of pore structure change is still an enigma. In this study, we try to unveil the pore structure evolution during weathering process through studying Cambrian Hetang shales in southern China. Fourteen shale samples, from protolith zone (PZ), fractured and weathered shale zone (FWZ), and saprolite zone (SZ), were collected to elucidate how porosity and pore structure develop during black shale weathering under subtropical condition. Through low pressure argon (Ar) gas adsorption (LP-ArGA), high pressure mercury intrusion (HPMI), nuclear magnetic resonance(NMR) and field emission scanning electron microscope (FESEM) observation, the results reveal significant differences in physical properties and pore structures among the PZ, FWZ, and SZ samples. Specifically, compared to PZ, FWZ and SZ samples are characterized by higher clay mineral content, lower organic matter (OM), and the absence of carbonates and pyrite. Total porosity, determined through HPMI and NMR, exhibits a gradual increase from PZ (6.70 % and 6.41 %) to FWZ (20.47 % and 13.45 %) and SZ (23.22 % and 12.48 %). Ar adsorption isotherms indicate a change in pore type from predominantly ink-bottle and slit-shaped in the PZ to mainly slit-shaped in FWZ and SZ. Integrated analysis of LP-ArGA, HPMI, NMR and SEM observation suggests a substantial decrease in the contribution of micropores to total pore volume (PV) and a concurrent increase in larger pores (meso-macropores) with the increase of weathering intensity. This results in smoother surfaces of micro-transition pores but rougher surfaces of macropores. Changes in mineralogy composition during weathering play a crucial role in influencing pore structure of shales and further accelerating the release and migration of toxic elements in black shale. Our study provides the essential theoretical foundation for the remediation of soil and water environmental pollution caused by black shale weathering.

Synthesis and photocatalytic properties of Cerium(IV) oxide graphene oxide composites

Semiconductor photocatalytic technology is a simple, efficient, and low-cost method for environmental pollution remediation. Cerium dioxide (CeO2), as a promising oxidative degradation photocatalyst, can solve the problems of energy shortage and environmental pollution. In this paper, cerium dioxide/graphene oxide composites were successfully synthesized by a one-pot hydrothermal method, achieving a degradation rate of 88.96 % for rose red dye in 150 min, and the introduction of reduced graphene oxide effectively improves the photocatalytic performance of pure cerium oxide.

Calcium-Based Metal-Organic Framework: Detection and Idiosyncratic Removal of Copper by Nano-Particle Deposition.

A novel calcium-based metal-organic framework (CaMOF@LSB) was designed and synthesized, exhibiting dual functionality for both selective detection and removal of Cu2+ ions from aqueous solutions. The framework's stability, including solvent and pH variations, was established with notable thermal resilience. Colorimetric Cu2+ detection (≥5 ppm) with a high capture capacity of 484.2 mg g-1 by CaMOF@LSB places this material among the few that ensure efficient colorimetric detection and high removal capabilities of Cu2+ ions. Batch adsorption experiments revealed pH-dependent behavior and competitive interactions. Langmuir and pseudo-second-order kinetics models aptly described adsorption isotherms and kinetics, respectively. Thermodynamic assessments confirmed spontaneous and endothermic adsorption. Mechanistically, nanoparticle deposition contributes to the Cu2+ uptake. CaMOF@LSB also exhibited one of the best removal behaviour of Cu2+ by means of oxide formation on the surface. Regeneration of CaMOF@LSB was achieved by simple sonication in 0.1 M aqueous NaOH solution. The recyclability was also tested up to 5 cycles, and it exhibited a small decrease in adsorption capacity observed across the cycles. This research presents a promising avenue for addressing heavy metal pollution using metal-organic frameworks, thereby offering potential applications in water purification and environmental pollution monitoring and remediation.

Characterization of novel pectin zirconium tungstosilicate hybrid ion exchanger and its adsorptive remediation of environmental pollutants

Characterization of novel pectin zirconium tungstosilicate hybrid ion exchanger and its adsorptive remediation of environmental pollutants

Biogenic production of eco-friendly Arjuna-ZnO NPs for sunlight-activated efficient degradation of organic dyes of high commercial usage

The present study describes an environmentally benign biological method for the production of zinc oxide nanoparticles (ZnO NPs) by blending water-based leaf extract from a sustainable bio-source, the Arjuna tree, under ambient conditions. Aqueous leaf extract comprised of different reducing agents appeared as the precursor for phytofabrication, and zinc nitrate hexahydrate (ZnNO3·6H2O) acted as a zinc source. The phytofabricated Arjuna-ZnO NPs had a hexagonal shape with an average size of 31.14 nm, as revealed by HR-TEM, FE-SEM micrographs, and XRD patterns. The FESEM-EDS micrograph and the XRD patterns also revealed the elemental composition, phase purity, and crystalline nature of phytofabricated Arjuna-ZnO NPs. The initial formation of ZnO NPs was confirmed by absorption maxima at approximately 376 nm and Zn-O stretching vibrations at 520 cm−1 using UV–VIS and an FT-IR spectrophotometers, respectively. The aqueous extract of Arjuna leaf was also analysed using FT-IR spectrophotometer to identify the functional groups of bioactive substances that participated in the reduction and encapsulation processes. The efficacy of the Arjuna-ZnO NPs was assessed in terms of their ability to photocatalyzed on three noxious dyes, methylene blue (MB), methyl orange (MO), and congo red (CR), for high commercial and industrial usage. The phytofabricated Arjuna-ZnO NPs were photoactive and proved highly efficient and effective nano-photocatalysts for the photodegradation of three dyes, MB, MO, and CR, under natural sunshine, underscoring their potential for effective remediation of environmental pollutants. The degradation process adhered to pseudo-first-order kinetics in terms of adsorption kinetics.

A novel nano-cerium oxide functionalized biochar composite for degradation of organic dye: insight of the photocatalysis mechanism.

Recently, visible-light-driven photocatalysis attracts much concerns in the remediation of environmental organic pollutants. In this study, the cerium doped biochar was fabricated through the hydrothermal method, and served as an efficient photocatalyst towards rhodamine B degradation under visible light irradiation. Almost 100% of rhodamine B was removed by 2.0g·L-1 cerium doped biochar after 60min of visible light irradiation at pH 3, but only about 25.50% and 29.60% of rhodamine B was removed by cerium dioxide and biochar under identical conditions. The degradation process coincided well with the pseudo-first-order kinetic model, and the photodegradation rate constant of cerium doped biochar was 0.0485·min-1, which was respectively 97 and 44 times that of biochar (0.0005·min-1) and cerium dioxide (0.0011·min-1). According to the trapping experiments and electron spin resonance spectroscopy analysis, h+, O2-∙ and ∙OH all participated in the degradation of rhodamine B in the cerium doped biochar photocatalytic systems, and the function of h+ and ∙OH was dominated. Consequently, the biochar could not only be an excellent carrier for supporting cerium dioxide, but also greatly improved its photocatalytic activity. The band gap of cerium doped biochar was narrower than cerium dioxide, which could improve the separation and migration of photogenerated electron-hole pairs under visible-light excitation, thus ultimately enhanced the degradation of rhodamine B. This work provided a deeper understanding of the preparation of biochar-based photocatalyst and its application in the remediation of environmental organic pollution.

Synergistic degradation of oxytetracycline hydrochloride by persulfate activated by Ni-doped MIL-88A three-dimensional catalyst: Free radical and non-free radical pathways

The advanced oxidation technology of persulfate has great potential in removing pollutants. Appropriate bimetallic activation method has obvious synergistic effect on the formation of free radicals and non-free radicals, and can also promote the electron transfer process. Therefore, in this paper, Ni was doped on the iron-based metal organic framework (MIL-88A) to form bimetallic catalyst and used as persulfate activator for oxytetracycline (OTC) degradation. The introduction of Ni increased the specific surface area of the catalyst and significantly improved its catalytic performance. Within 30 min, the degradation efficiency of 5 mg/L OTC reached 81.30%. The used catalyst can be simply recovered by standing, and the catalytic stability is high. The composition of main reactive oxygen species (ROS) in pollutant decomposition was clarified through the analysis of degradation mechanism. In addition to typical •OH、SO4•− and O2•−, non-free radical 1O2 was also generated. Based on LC-MS detection and toxicological experiments, the possible degradation pathways were proposed and the toxicity was analyzed. This material provides a new insight for activating PS to remove refractory organic compounds, and promotes the application of Fe-MOF materials in environmental pollution remediation.

Metal-Organic Frameworks-Derived Nanocarbon Materials and Nanometal Oxides for Photocatalytic Applications.

Harnessing low-density solar energy and converting it into high-density chemical energy through photocatalysis has emerged as a promising avenue for the production of chemicals and remediation of environmental pollution, which contributes to alleviating the overreliance on fossil fuels. In recent years, metal-organic frameworks (MOFs) have gained widespread application in the field of photocatalysis due to their photostability, tunable structures, and responsiveness in the visible light range. However, most MOFs exhibit relatively low response to light, limiting their practical applications. MOFs-derived nanomaterials not only retain the inherent advantages of pristine MOFs but also show enhanced light adsorption and responsiveness. This review categorizes and summarizes MOFs-derived nanomaterials, including nanocarbons and nanometal oxides, providing representative examples for the synthetic strategies of each category. Subsequently, the recent research progress on MOFs-derived materials in photocatalytic applications are systematically introduced, specifically in the areas of photocatalytic water splitting to H2, photocatalytic CO2 reduction, and photocatalytic water treatment. The corresponding mechanisms involved in each photocatalytic reaction are elaborated in detail. Finally, the review discusses the challenges and further directions faced by MOFs-derived nanomaterials in the field of photocatalysis, highlighting their potential role in advancing sustainable energy production and environmental remediation.

Biochar: A Comprehensive Review on a Natural Approach to Plant Disease Management

Since time immemorial organic amendments have been an important strategy for improving soil fertility and suppressing a wide range of soil-borne pathogens. Biochar, a charcoal-like amendment has true potential in managing phytopathogens with an eco-friendly approach. It is produced by subjecting plant materials and agricultural waste to high temperatures of around 900°C in limited oxygen conditions. Biochar is considered to be an excellent carbon sequester and has an undeniably imperative role in improving soil properties. Biochar has innumerable applications in the remediation of environmental pollutants by immobilizing heavy metals such as Cadmium and Arsenic and degradation of dyes and pesticides. One of the most significant advantages of biochar in addition to mitigating environmental pollution is effectively managing plant pathogens by altering soil physical and chemical properties and promoting antagonistic microorganisms. Biochar directly suppresses plant pathogens by priming plant defense mechanisms. For instance, sugarcane bagasse biochar remediates Cd from contaminated soil, and citrus wood biochar induces systemic resistance against Botrytis cinerea in host-Lycopersicon esculentum, Capsicum annuum L. cv. Maccabi and Fragaria ananassa. Nevertheless, it is essential to acknowledge its limitations, such as the potential to absorb and enhance the residual activity of harmful chemicals. Further research is needed to develop a deeper understanding of biochar’s properties and mechanisms for more effective results. Advanced techniques like meta-transcriptomics and metaproteomics hold the potential to provide invaluable insights into this field. The review provides a comprehensive overview of current information regarding biochar, covering its production techniques and highlighting its agricultural benefits, with a particular focus on its role in plant disease management. Furthermore, the associated risks and concerns are also discussed.

Mycogenic synthesis of iron nanoparticles using thermophilic mould Myceliophthora thermophila and their applicability in environmental remediation

Culture extract of thermophilic mould Myceliophthora thermophila BJTLRMDU7 played important role in the green synthesis of iron nanoparticles (FeNPs) using ferrous sulphate (FeSO4). The mould was grown in potato dextrose broth (PDB) at 45 °C and 200 rpm for 72 h. A colour change from transparent to reddish brown showed the synthesis of FeNPs due to the surface plasmon resonance by the fungal culture extract. The process for the synthesis of nanoparticles was optimized using different reaction conditions. Biogenic iron nanoparticles were synthesized maximally at 50 °C and pH 5.0 after 24 h using 2 mM salt solution and one ml culture extract. Furthermore, formation of iron nanoparticles was significantly accelerated in the presence of light. The absorption peak was maximum around 250–350 nm in UV–vis spectrum. The absorption peaks of Fourier-transform infrared spectroscopy (FTIR) at 619.99 cm−1, 793.57 cm−1, 882.32 cm−1, 1121.46 cm−1, 1627.71 cm−1, 2923.17 cm−1 and 3430.70 cm−1, indicated functional groups of active biomolecules involved in the synthesis of FeNPs. Atomic force microscopy (AFM) images of green synthesized iron nanoparticles indicated the average size of 80 nm, while X-ray diffraction (XRD) data revealed the crystalline nature of FeNPs. These FeNPs efficiently reduced p-nitrophenol (PNP) into p-aminophenol (PAP), which was further confirmed by thin layer chromatography. Biogenic FeNPs showed 96 and 35 % decolourization of bromphenol blue and malachite green, respectively. Further, addition of H2O2 enhanced the decolourization of malachite green up to 96 %. Biogenic FeNPs synthesized from culture extract of a thermophilic mould have been found effective in remediation of environmental pollutants released from various industries.

Regulable surface hydroxyl group content in disperse ultrafine amorphous SiO2 nanoparticles

AbstractAmorphous silica (SiO2) nanoparticles (NPs) can be applied in environmental pollutant remediation, element removal, and water purification. The content of surface silanol groups in amorphous SiO2 NPs affects the characteristics of SiO2 NPs. However, the regulation of surface silanol group content in amorphous SiO2 NPs below 10 nm remains a challenge. Herein, tunable surface silanol group content was achieved in disperse ultrafine amorphous SiO2 NPs by controlling calcination and rehydroxylation. The surface silanol group content in amorphous SiO2 NPs is low (10 nm) and can be tuned from 0% to 2.5%. The amount of naphthalene adsorbed by the SiO2 NPs increases with increasing surface silanol group content. The surface silanol group content in SiO2 NPs can be an effective means to tune their adsorption performance and applications.

Comparative study of visible-light active BiOI and N,Pd-TiO2 photocatalysts: Catalytic ozonation for dye degradation

The increasing demand for clean water requires the development of simple, cheap, and efficient catalysts systems for water pollution remediation. To develop cheap yet efficient hybrid advanced oxidation processes for degradation of organic pollutants in water requires their systematic comparison under similar conditions to make informed decisions of economically feasible and sustainable systems. Visible light active single BiOI and N, Pd co-doped TiO2 were investigated for photocatalytic ozonation (PCO) for methylene blue (MB) degradation. Metal and non-metal co-doping improved morphology, band structure and active sites on the surface of TiO2 to shift its light absorption into the visible region. The degradation of MB with BiOI PCO and N,Pd-TiO2 PCO was practically similar but showed improvement of the ozonation mineralization efficiency. However, mineralization of MB on BiOI PCO surpassed that of N,Pd-TiO2 PCO due to band structure that influenced generated free radicals during the PCO processes. BiOI PCO system progressed through the existence and involvement of strongly oxidizing and non-selective hydroxyl radicals towards enhanced mineralization of dye and intermediates while N,Pd-TiO2 PCO was steered by the superoxide radical that is selective and had lower mineralization efficiency of formed intermediates despite its high initial degradation efficacy. The work demonstrated cheap and efficient visible light active semiconductors like BiOI as potential candidates for application in photocatalytic ozonation for real applications with matching activities to that of co-doped UV active semiconductors like TiO2. This work advances the use of visible light active semiconductors towards PCO based processes for environmental pollution remediation.

Integration of 2D graphene oxide/zinc oxide nanohybrid for enhancement adsorption and photodegradation of organic pollutants

The band gap plays a critical role in determining the photocatalytic efficiency of semiconductor catalysts. Zinc oxide (ZnO) photocatalysts have gained significant attention in sustainable energy and environmental pollution remediation. However, despite its potential, ZnO photocatalytic performance has been hindered by its wide band gap and rapid charge carrier recombination. Numerous techniques have been created to tackle this problem, including doping, nanostructuring, creating oxygen defects, surface modification, and utilizing hybrid nanomaterials. The ZnO and ZnO@GO with different GO contents were synthesized using uncomplicated co-precipitation and solid-state reaction techniques. The ZnO@GO possesses bandgap (Eg) values of 2.5 eV, which is advantageous for achieving more significant photocatalytic activity compared to the unadorned ZnO with Eg values of 3.24 eV. This study investigated the effectiveness of the synthesized catalysts in treating methylene blue (MB) dye through visible light-induced photoreaction. The ZnO@GO nanohybrid exhibited remarkable performance, achieving a decomposition rate of 98.4 % for MB within a 22-minute timeframe. The rate constant of 0.1343 min−1 is significantly greater than that of the unadorned ZnO 0.0448 min−1. Graphene oxide (GO) plays a crucial role in the photocatalytic process by facilitating the gathering and transportation of electrons. This enhancement generates reactive oxygen species and hydroxyl radicals, effectively breaking down MB. The scavenger test results provided compelling evidence that the degradation of MB primarily occurred due to the presence of hydroxyl radicals, which were identified as the most active species in this process.

Recent trends and economic significance of modified/functionalized biochars for remediation of environmental pollutants

The pollution of soil and aquatic systems by inorganic and organic chemicals has become a global concern. Economical, eco-friendly, and sustainable solutions are direly required to alleviate the deleterious effects of these chemicals to ensure human well-being and environmental sustainability. In recent decades, biochar has emerged as an efficient material encompassing huge potential to decontaminate a wide range of pollutants from soil and aquatic systems. However, the application of raw biochars for pollutant remediation is confronting a major challenge of not getting the desired decontamination results due to its specific properties. Thus, multiple functionalizing/modification techniques have been introduced to alter the physicochemical and molecular attributes of biochars to increase their efficacy in environmental remediation. This review provides a comprehensive overview of the latest advancements in developing multiple functionalized/modified biochars via biological and other physiochemical techniques. Related mechanisms and further applications of multiple modified biochar in soil and water systems remediation have been discussed and summarized. Furthermore, existing research gaps and challenges are discussed, as well as further study needs are suggested. This work epitomizes the scientific prospects for a complete understanding of employing modified biochar as an efficient candidate for the decontamination of polluted soil and water systems for regenerative development.

Bacillus Species with Dye-remediation Potential – A Mini Review

Dyes are either natural or synthetic pigments used as colour for different items including textile materials, leather, cosmetics, plastic, paper, printing ink, food, human hair or paintings. The persisting colour and toxic compounds contained in most dyes leads to serious environmental pollution which is unsuitable for the survival of many ecologically important organisms. A wide range of bacterial species have been reported to effectively remediate dyes of various types and classes. This paper reviews bacterial species from the genus Bacillus with the potentiality to remediate synthetic dyes based on published literatures. Bacillus species remediate dyes basically through biosorption and enzymatic active. The most commonly used Bacillus species are Bacillus subtilis, B. cereus, B. megaterium, B. fusiformis, B. odysseyi, B. mycoides, B. paramycoides, B. pseudomycoides, B. flexus, B. cohnii, B. licheniformis, B. spizizenii, B. algicola, B. vallismortis, B. vietnamensis, B. stratosphericus, B. halodurans, B. albus, B. aryabhattai and B. velezensis. Other researches have also proven that mixed cultures of Bacillus species and species from other microbial genera display significant efficiency in the remediation of various dyes. These species produce enzymes and compounds that aid in the breakdown of dyes, thus, reducing their impact to the environment. The use of the aforementioned Bacillus species in the remediation of other dye related environmental pollutants is highly recommended.

Selective Oxidation Using In Situ-Generated Hydrogen Peroxide.

ConspectusHydrogen peroxide (H2O2) for industrial applications is manufactured through an indirect process that relies on the sequential reduction and reoxidation of quinone carriers. While highly effective, production is typically centralized and entails numerous energy-intensive concentration steps. Furthermore, the overhydrogenation of the quinone necessitates periodic replacement, leading to incomplete atom efficiency. These factors, in addition to the presence of propriety stabilizing agents and concerns associated with their separation from product streams, have driven interest in alternative technologies for chemical upgrading. The decoupling of oxidative transformations from commercially synthesized H2O2 may offer significant economic savings and a reduction in greenhouse gas emissions for several industrially relevant processes. Indeed, the production and utilization of the oxidant in situ, from the elements, would represent a positive step toward a more sustainable chemical synthesis sector, offering the potential for total atom efficiency, while avoiding the drawbacks associated with current industrial routes, which are inherently linked to commercial H2O2 production. Such interest is perhaps now more pertinent than ever given the rapidly improving viability of green hydrogen production.The application of in situ-generated H2O2 has been a long-standing goal in feedstock valorization, with perhaps the most significant interest placed on propylene epoxidation. Until very recently a viable in situ alternative to current industrial oxidative processes has been lacking, with prior approaches typically hindered by low rates of conversion or poor selectivity toward desired products, often resulting from competitive hydrogenation reactions. Based on over 20 years of research, which has led to the development of catalysts for the direct synthesis of H2O2 that offer high synthesis rates and >99% H2 utilization, we have recently turned our attention to a range of oxidative transformations where H2O2 is generated and utilized in situ. Indeed, we have recently demonstrated that it is possible to rival state-of-the-art industrial processes through in situ H2O2 synthesis, establishing the potential for significant process intensification and considerable decarbonization of the chemical synthesis sector.We have further established the potential of an in situ route to both bulk and fine chemical synthesis through a chemo-catalytic/enzymatic one-pot approach, where H2O2 is synthesized over heterogeneous surfaces and subsequently utilized by a class of unspecific peroxygenase enzymes for C-H bond functionalization. Strikingly, through careful control of the chemo-catalyst, it is possible to ensure that competitive, nonenzymatic pathways are inhibited while also avoiding the regiospecific and selectivity concerns associated with current energy-intensive industrial processes, with further cost savings associated with the operation of the chemo-enzymatic approach at near-ambient temperatures and pressures. Beyond traditional applications of chemo-catalysis, the efficacy of in situ-generated H2O2 (and associated oxygen-based radical species) for the remediation of environmental pollutants has also been a major interest of our laboratory, with such technology offering considerable improvements over conventional disinfection processes.We hope that this Account, which highlights the key contributions of our laboratory to the field over recent years, demonstrates the chemistries that may be unlocked and improved upon via in situ H2O2 synthesis and it inspires broader interest from the scientific community.

Nanomaterials for Potential Detection and Remediation: A Review of Their Analytical and Environmental Applications

The rapid increase in industrialization and human population is leading to critical levels of environmental pollutants, such as agrochemicals or heavy metals, which affect the preservation and integrity of ecosystems, the accessibility to drinking water sources, and the quality of the air. As such, remediation of these issues demands strategies for implementing and designing novel technologies. In that regard, nanomaterials have unique physicochemical properties that make them desirable candidates for the detection and remediation of environmental pollutants. The scope of this review is to provide an analysis of the available nanomaterials that are being used as an approach to detect and remediate hazardous residues, comprising systems such as noble metals, biosensors, cyclodextrin-based polymers, and graphene oxide nanocomposites, to name a few. Furthermore, this work discusses said nanomaterials in terms of their effectiveness, sustainability, and selectivity as a guideline for researchers wishing to indulge in this relevant study area.

A systematic review of lignocellulosic biomass for remediation of environmental pollutants

Lignocellulosic wastes are the most promising feedstock, as they are the most inexpensive and abundantly renewable natural resource. The abundance of cellulose, lignin, and hemicellulose in feedstocks has been shown to be effective in eliminating persistent contaminants. Environmental issues, including the accumulation of agricultural waste, waste water treatment, and air pollution, could be resolved by producing value-added products like activated carbon from these wastes. Several biomass wastes were used to produce activated carbon using a two-step processing method that involved oxygen-free carbonisation and activation. This study examines the methods for making biochar from different lignocellulosic biomass sources. Furthermore, biochar modification significantly modifies surface area and pore volume. To determine the fundamental characteristics of biochar and to evaluate its potential for use in a variety of environmental applications, physical and chemical characterizations are required. Various widely used modern analytical techniques, such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), nuclear magnetic resonance spectroscopy (NMR), Brunauer-Emmett-Teller (BET), and Raman spectroscopy, have been reviewed in this work. The potential mechanisms through which lignocellulosic biochars may absorb pollutants are outlined. In general, this review highlights the significance and potential of activated carbon formed from waste products for environmental remediation, demonstrating that biomass-originated activated carbon could have a significant impact on increasing economic viability and efficiently protecting the environment.