It is well known that urbanization and industrialization have resulted in the rapidly increasing emissions of volatile organic compounds (VOCs), which are a major contributor to the formation of secondary pollutants (e.g., tropospheric ozone, PAN (peroxyacetyl nitrate), and secondary organic aerosols) and photochemical smog. The emission of these pollutants has led to a large decline in air quality in numerous regions around the world, which has ultimately led to concerns regarding their impact on human health and general well-being. Catalytic oxidation is regarded as one of the most promising strategies for VOC removal from industrial waste streams. This Review systematically documents the progresses and developments made in the understanding and design of heterogeneous catalysts for VOC oxidation over the past two decades. It addresses in detail how catalytic performance is often drastically affected by the pollutant sources and reaction conditions. It also highlights the primary routes for catalyst deactivation and discusses protocols for their subsequent reactivation. Kinetic models and proposed oxidation mechanisms for representative VOCs are also provided. Typical catalytic reactors and oxidizers for industrial VOC destruction are further discussed. We believe that this Review will provide a great foundation and reference point for future design and development in this field.

/pdf/recent-advances-in-the-catalytic-oxidation-of-volatile-zw2c35dbg7.pdf

Recent Advances in the Catalytic Oxidation of Volatile Organic Compounds: A Review Based on Pollutant Sorts and Sources.

This exhaustive review focuses on the fundamental principles and applications of heterogeneous electrochemical wastewater treatment based on Fenton’s chemistry reaction. The elementary equations involved in formation of hydroxyl radical in homogeneous electro-Fenton (EF) and photo electro-Fenton (PEF) processes was presented and the advantages of using insoluble solids as heterogeneous catalyst rather than soluble iron salts (heterogeneous electro-Fenton process) (Hetero-EF) was enumerated. Some of the required features of good heterogeneous catalysts were discussed, followed by the mechanisms of catalytic activation of H2O2 to reactive oxygen species (ROS) especially hydroxyl radical ( OH) by heterogeneous catalyst in Hetero-EF system. Extensive discussion on the two configuration of Hetero-EF system vis-a-vis added solid catalysts and functionalized cathodic materials were provided along with summaries of some relevant studies that are available in literature. The solid catalysts and the functionalized cathodic materials that have been utilized in Hetero-EF wastewater treatment were grouped into different classes and brief discussion on their synthesis route were given. Besides, the use of solid catalysts and iron-functionalized cathodic materials in bioelectrochemical system (BES) especially bioelectro-Fenton technology (BEF) using microbial fuel cells (MFCs) with concurrent electricity generation for Hetero-EF treatment of biorefractory organic pollutants was discussed. In the final part, emphasis was made on the challenges and future prospects of the Hetero-EF for wastewater treatment.

Heterogeneous electro-Fenton and photoelectro-Fenton processes: A critical review of fundamental principles and application for water/wastewater treatment

Recent advances in aerogels for environmental remediation applications: A review

The presence of an excessive concentration of CO2 in the atmosphere needs to be curbed with suitable measures including the reduction of CO2 emissions at stationary point sources such as power plants through carbon capture technologies and subsequent conversion of the captured CO2 into non-polluting clean fuels/chemicals using photo and/or electrocatalytic pathways. Porous materials have attracted much attention for carbon capture and in the recent past; they have witnessed significant advancements in their design and implementation for CO2 capture and conversion. In this context, the emerging trends in major porous adsorbents such as MOFs, zeolites, POPs, porous carbons, and mesoporous materials for CO2 capture and conversion are discussed. Their surface texture and chemistry, and the influence of various other features on their efficiency, selectivity, and recyclability for CO2 capture and conversion are explained and compared thoroughly. The scientific and technical advances on the material structure versus CO2 capture and conversion provide deep insights into designing effective porous materials. The review concludes with a summary, which compiles the key challenges in the field, current trends and critical challenges in the development of porous materials, and future research directions combined with possible solutions for realising the deployment of porous materials in CO2 capture and conversion.

Emerging trends in porous materials for CO2 capture and conversion

The abrupt and massive deactivation of methane dry reforming catalysts especially Ni-based is still a monumental impediment towards its industrialization and commercialization for production of value-added syngas via Fischer-Tropsch process. The need for further and more critical understanding of inherent and tailored interactions of catalyst components for performance and stability enhancement during reforming reaction cannot be over-emphasized. This review provides a contemporary assessment of progresses recorded on synergistic interplay among catalyst components (active metals, support, promoters and binders) during dry reforming using state-of-the-art experimental and theoretical techniques. Advancements achieved during interplay leading to improvements in properties of existing catalysts and discovery of novel ones were stated and expatiated. Reaction pathways, catalytic activities, selection of appropriate synthesis route and metal/support deactivation via sintering or carbon deposition have over time been successfully studied and explained using information from these crucial component interactions. This perspective describes the roles of these interactions and their applications towards development of robust catalysts configurations for successful industrial applications.

A review on catalyst development for dry reforming of methane to syngas: Recent advances

CO2 capture and storage technologies have been recognized as the primary option to mitigate the issue of climate change caused by the utilization of fossil fuels. In the last decades, several CO2 c ...

Alternative pathways for efficient CO2 capture by hybrid processes—A review

Monolithic Co3O4 and Co3O4@MnOx catalysts have been successfully prepared by in-situ growth. The morphology control and formation mechanism of Co3O4 on Ni foam was investigated in detail. Among the different samples, bamboo leaf-like Co3O4-NF-10 presented good catalytic activity for acetone oxidation (T50 = 179 °C, T90 = 193 °C), which was attributed to its low temperature reducibility, abundant Co3+ and surface adsorbed oxygen species (Oads). Therefore, Co3O4@MnOx-NF was further prepared to obtain abundant Co3+ and Oads species due to the redox reaction between MnO4− and Co2+. As expected, the Co3O4@MnOx-NF catalyst presented significantly improved activity for not only acetone but ethyl acetate and toluene oxidation compared to the Co3O4-NF-10. The high catalytic performance of Co3O4@MnOx-NF was ascribed to its good low-temperature reducibility, abundant Co3+ and Oads species. In addition, Co3O4@MnOx-NF presented a satisfactory cycle and long-term stability. This work shed light on the design of monolithic catalysts in VOC oxidation.

Novel monolithic catalysts derived from in-situ decoration of Co3O4 and hierarchical Co3O4@MnOx on Ni foam for VOC oxidation

Optimization of steam methane reforming coupled with pressure swing adsorption hydrogen production process by heat integration

As a natural renewable resource, the catalytic conversion of lignocellulosic biomass is considered to be an important strategy to alleviate the tremendous dependence on fossil resources. The synthesis of γ-valerolactone (GVL), which is hailed as a new-generation of biomass-based platform molecule, is one of the pivotal steps in the transformation of biomass resources into liquid fuels and high-value chemicals. The catalytic routes for the synthesis of GVL from lignocellulosic feedstocks have been continuously enriched and improved in recent years. Herein, our principal focus is the reaction mechanisms and catalytic systems of GVL from various biomass-derived feedstocks. The specific reaction routes and catalytic performances of GVL synthesis based on the traditional basic raw materials such as levulinic acid (LA) and alkyl levulinates (AL) were discussed and compared, and one-pot processes with cascade steps of cellulosic and hemicellulosic derivatives such as furfural (Fur), furfuryl alcohol (FAL) as well as cellulosic carbohydrates into GVL were also summarized and analyzed in detail. A more intuitive and comprehensive retrospection of the up-to-date literatures on GVL synthesis through multiple pathways was presented, and practical suggestions on improving the cost, stability and efficiency of the overall catalytic systems were also proposed.

Na Ji

Papers

Alternative pathways for efficient CO2 capture by hybrid processes—A review

Novel monolithic catalysts derived from in-situ decoration of Co3O4 and hierarchical Co3O4@MnOx on Ni foam for VOC oxidation

Optimization of steam methane reforming coupled with pressure swing adsorption hydrogen production process by heat integration

Synthesis of γ-valerolactone from different biomass-derived feedstocks: Recent advances on reaction mechanisms and catalytic systems

Reducing the energy consumption of membrane-cryogenic hybrid CO2 capture by process optimization