Addressing the CO ₂ challenge is mandatory for the well-being of Earth's ecosystem and humanity. CO ₂ catalytic hydrogenation is a suitable solution.

This review provides a state-of-the-art summary of distributed zeolite technology, as well as identifying strategies to further promote the absorption of these materials in various areas of study. Zeolites are materials that can be synthesized or found in natural rock deposits a with a basic composition consisting in Al, Si, and O. Zeolite’s consideration as a future material is due to many facile synthesis methods to obtain different structures with variations in pore size, surface area, pore volume and physical properties. These methods are developed using the control of relevant synthesis parameters that influences structure formation, such as crystallization temperature, time of aging and/or crystallization, stoichiometric relationships between components of synthesis gel, pH of the medium, and in some cases the type of structure-directing agent. Each method will lead to geometric changes in the framework formation, making possible the formation of typical chemical bonds that are the fingerprint of any zeolitic structure (O-Si-O and Al-O-Si), forming typical acid sites that give specificity in zeolite and allows it to act as a nanoreactor. The specificity is a characteristic that in some cases depends on selectivity, a fundamental property derived of the porosity, mostly in processes that occur inside the zeolite. In processes outside the structure, the surface area is the main factor influencing this property. Moreover, there are many natural sources with adequate chemical composition to be used as precursors. Some of these sources are waste, minimizing the deposition of potential hazardous materials that can be recalcitrant pollutants depending on the environment. Besides its uses as a catalyst, zeolite serves as a support for many bioprocesses; therefore, this review aims to explain relevant aspects in chemical nature, physical properties, main methods of synthesis, main precursors used for synthesis, and relevant applications of zeolites in chemical catalysis and biological processes.

The total annual production of agricultural biomass such as wood, corn cobs, leaves, and citrus peels, is estimated at 956 million tons (Mt). Since crop residues are by-products of agricultural production, crop residue collection does not compete with food crops for acreage and therefore, it does not negatively impact food prices. Moreover, it has the advantage of reducing the amount of waste, the disposal of which often becomes a serious problem despite natural sources. Biomass conversion becomes a very valid alternative to diversify energy sources and reduce global warming. Thermochemical treatment of biomass is a promising way to convert biomass into bio-oil, biochar, and gas. In recent years, interest in the conversion of plant biomass into biochar has increased because this carbonaceous material has interesting properties that guarantee applications in wastewater treatment, soil improvement, solid fuels, and energy. The processes performed to convert biomass into biochar are different and the most used are thermochemical processes: pyrolysis, torrefaction, hydrothermal treatment, and gasification. The studies of the thermokinetic parameters that control these processes are carried out using different methods that provide the necessary information for the applicability of the processes on an industrial scale. One of the objectives of the present review is to compare kinetic models in order to clarify the role of the conversion process and the effects of the process parameters on the final product. A comprehensive investigation of the thermokinetic parameters controlling the conversion of crop residues to biochar was conducted. The mathematical description of kinetic processes is usually performed using the Arrhenius equation and its derivatives to obtain the activation energies (E_a), the pre-exponential parameter, and the process mechanisms. While isothermal processes can be described using the model fitting method, isoconversional processes can be studied using both the model fitting method and model-free methods. The high complexity and diversity of the reactions involved could lead to the use of approximations. In this paper, an overview of the kinetic parameters determined for biochar production processes and the model used to determine them is given.

Correction for ‘Hydrochar from Sargassum muticum : a sustainable approach for high-capacity removal of Rhodamine B dye’ by D. Spagnuolo et al. , RSC Sustain. , 2023, 1 , 1404–1415, https://doi.org/10.1039/D3SU00134B.