Valorization of Raw and Calcined Chicken Eggshell for Sulfur Dioxide and Hydrogen Sulfide Removal at Low Temperature

Agri-food waste biosorbents for volatile organic compounds removal from air and industrial gases - A review

Approximately 1.3 billion metric tons of agricultural and food waste is produced annually, highlighting the need for appropriate processing and management strategies. This paper provides an exhaustive overview of the utilization of agri-food waste as a biosorbents for the elimination of volatile organic compounds (VOCs) from gaseous streams. The review paper underscores the critical role of waste management in the context of a circular economy, wherein waste is not viewed as a final product, but rather as a valuable resource for innovative processes. This perspective is consistent with the principles of resource efficiency and sustainability. Various types of waste have been described as effective biosorbents, and methods for biosorbents preparation have been discussed, including thermal treatment, surface activation, and doping with nitrogen, phosphorus, and sulfur atoms. This review further investigates the applications of these biosorbents in adsorbing VOCs from gaseous streams and elucidates the primary mechanisms governing the adsorption process. Additionally, this study sheds light on methods of biosorbents regeneration, which is a key aspect of practical applications. The paper concludes with a critical commentary and discussion of future perspectives in this field, emphasizing the need for more research and innovation in waste management to fully realize the potential of a circular economy. This review serves as a valuable resource for researchers and practitioners interested in the potential use of agri-food waste biosorbents for VOCs removal, marking a significant first step toward considering these aspects together.

Synthesis of hydroxyapatite from eggshells via wet chemical precipitation: a review

In conjunction with the global trend towards sustainable industry, this review provides a summary of the research endeavors and efforts made in the field of exploiting eggshells in the production of hydroxyapatite (HA). HA is one of the most used biomaterials and has attracted considerable attention over the years towards biomedical applications. As the traditional production of HA from calcium and phosphorus chemical precursors synthetically has bottlenecks of being expensive, complex, time consuming, and results in a low biocompatible product, natural resources have become an attractive alternative option to synthesize HA, with trace elements providing a higher performance. Eggshell, with a growing production annually, is potentially a promising natural resource for HA production. Many studies have used different wet chemical precipitation routes to produce HA with properties comparable to synthetic HA. Thus, this review provides an overview of the various routes that can be used to synthesize HA from eggshells. In this review, the synthesis of HA from eggshells via wet chemical precipitation methods is specifically discussed in term of synthesis parameters and properties of the synthesized HA. This review should aid in choosing the most suitable route for HA production with the optimum parameters for obtaining the desired properties to meet the requirements of biomedical applications such as tissue engineering.

Thermodynamic Characteristics of the Hydrogen Sulfide Sorption Process by Ferromanganese Materials

The work analyzes hydrogen sulfide sorption from model gas mixtures containing H₂S from 1.25 × 10^-3 to 1.28 × 10^-4 mol/L under static conditions at temperatures 253 and 298 K on the raw manganese ore of the Ulu-Telyak deposit (Bashkortostan, Russia), manganese(IV) oxide, and manganese(IV) and iron(III) oxide mixtures. The thermodynamic models for calculating the equilibrium constants and Gibbs energy changes were analyzed. The sorption isotherms were described by the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich models. The value of enthalpy of hydrogen sorption on the ore was -68.98 ± 3.45 kJ/mol and those on model mixtures Mn₄ + Fe₂O₃ and MnO₄ were ±12.20 kJ/mol and -103.826 ± 5.19 kJ/mol, respectively, and the entropies of the hydrogen sulfide sorption process on three manganese materials at 253 K were calculated. The limiting capacity values of manganese materials at 253 and 298 K were obtained. The morphological analysis of the ore samples, Mn₄ + Fe₂O₃, and MnO₄, before and after hydrogen sulfide sorption, was carried out at 253 K. The obtained thermodynamic parameters determine the advantage of using the raw manganese ore over pure oxides, which characterizes its effective practical application in the desulfurization process.

Heavy metals removal from landfill leachate by coagulation/flocculation process combined with continuous adsorption using eggshell waste materials

The use of agricultural waste materials to remove heavy metals from wastewater is attractive due to its simplicity and economic efficiency. In this study, the applicability of calcined eggshell waste materials (CES) for heavy metals removal from real wastewater were examined via transport column experiment preceded by coagulation/flocculation process.A column packed with granular activated carbon (GAC) is operated in parallel to CES column to evaluate the adsorptive attributes of CES. The findings are assessed from another set of column experiments consisting of sand followed by CES column to evaluate the effect of particulate matter (PM) on CES performance toward heavy metals removal. In coagulation experiment, alum addition at an optimum dose (3.0 g/L) reduced the total suspended solids (TSS) by 80%, whereas the Fe, Pb, Zn, Cu, Ni, and Cr were reduced by 80%, 77%, 76%, 73%, 56%, and 49%, respectively. Under the current applied hydrodynamic conditions, using sand column before CES column improved the removal efficiencies of Fe, Pb, Cu, Zn, Ni, and Cr from 50% to 92%, 55% to 93%, 60% to 87%, 53% to 76%, 45% to 65%, and 41% to 60%, respectively. The whole results illustrate that CES can be competitive to GAC for heavy metals removal from landfill leachate, mainly if applied after PM removal by sand filtration.

Catalysts and Processes for H2S Conversion to Sulfur

Hydrogen sulfide is one of the main waste products of the petrochemical industry; it is produced by the catalytic hydrodesulfurization processes (HDS) of the hydrocarbon feedstocks, and it is a byproduct from the sweetening of sour natural gas and from the upgrading of heavy oils, bitumen, and coals [...]

Catalysts and Processes for H2S Conversion to Sulfur

The hydrogen sulfide (H2S) is one of the main byproducts in natural gas plants, refineries, heavy oil upgraders, and metallurgical processes [...]

Research on High- and Low-Temperature Characteristics of Bitumen Blended with Waste Eggshell Powder

The sustainability of resources is presently a major global concern. Sustainable construction materials can be produced by applying biological waste to engineering. Eggshells, as biological waste, are usually dumped in landfills or discarded. This causes many environmental problems including malodor, noise pollution, and serious waste of resources. To solve these problems, this study combined eggshell waste with bitumen materials for bio-roads construction. This paper investigated the impact of biological waste eggshell powder on the high- and low-temperature characteristics of bitumen materials. Scanning electron microscopy (SEM) revealed the microstructure of eggshell powder. The interaction between eggshell powder and asphalt was analyzed using Fourier transform infrared spectroscopy (FT-IR). The high- and low-temperature characteristics were investigated using conventional performance tests, and dynamic shear rheometer (DSR) and bending beam rheometer (BBR) experiments. These results indicate that eggshell powder (1) has a rough and porous microstructure; (2) has no apparent chemical reaction with asphalt; and (3) improves the consistency, hardness, and high-temperature characteristics. However, it reduces the plastic deformation capacity of asphalt, and the low-temperature crack resistance of asphalt cannot be improved. The research demonstrated that the application of eggshell powder in asphalt is feasible and has long-term resource and environmental advantages.