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In this work, the author developed Ca4Fe9O17/biochar (CFB) via a green method through a facile co-precipitation procedure involving egg shells as calcium precursor and investigating its performance in single as well as binary solution of methylene blue (MB) and rhodamine B (RhB). The CFB nanocomposite was characterized by XRD, SEM, TEM, XPS, Raman, FTIR, BET, and VSM. ESR studies show the presence of hydroxyl (·OH) and superoxide (O2·¯) radicals, which are primary radical species for pollutant degradation. The average crystalline size of CFB nanocomposites was found to be 32.992 nm using XRD, whereas TEM analysis indicates a particle diameter of 35–36 nm. The degradation efficacy of MB and RhB dyes was achieved at 99.2% and 98.6%, respectively, in a single solution, whereas 99.4% and 99.2%, respectively, in a binary solution within 36 min. Additionally, an iron cluster was formed during the degradation process of MB dye. The degradation of organic contaminants and generation of iron clusters from the degraded dye products were both expedited by the remarkable extension effect of the Ca4Fe9O17 in the CFB nanocomposites. The three processes were achieved using CFB nanocomposite: (1) the advanced oxidation process; (2) degradation of MB and RhB dye in single as well as binary solution with enhanced efficiency, (3) the production of the iron cluster from degraded products. Thus, these three steps constitute a smart and sustainable way that leads to an effective effluent water treatment system and the generation of iron clusters preventing secondary pollution. [ABSTRACT FROM AUTHOR]

Growing biodiesel production creates a significant volume of glycerol (Gly), a by-product that must be transformed into valuable compounds by developing novel and sustainable technologies. Solketal is one of several valuable compounds derived from residual Gly released during biodiesel synthesis. A green synthetic process followed by the co-precipitation method was used to fabricate NiS@Functionalized Biochar (NBS) using Azadrichta indica leaf extract. The nanocatalyst was extremely active for microwave-assisted solketal synthesis from Gly and acetone. A 99.7 ± 0.3 % conversion of Gly with 100 % solketal selectivity occurred under the optimum reaction conditions (catalyst loading 4 wt%, Gly to acetone molar ratio 1: 5, reaction time 6 min, and temperature 65 °C). The suggested reaction mechanism demonstrates the selective synthesis of solketal. The NBS catalyst showed excellent reusability up to six cycles, and after that, it was used for the photodegradation of tinidazole, where 89.14 % degradation efficiency was obtained within 110 min of sunlight irradiation. A narrow energy band gap (1.99 eV) and effective charge separation favor the photocatalytic activity of the reused catalyst. The environmental friendliness of the catalyst for the solketal synthesis process was examined by studying green metrics. [Display omitted] [ABSTRACT FROM AUTHOR]

This study reports the successful synthesis of an acid-functionalized ZnS/Biochar (ZBC-SO 3 H) nanocatalyst through a co-precipitation method utilizing Camellia sinensis leaf extract. The ZBC-SO 3 H nanocatalyst was employed for the microwave-assisted acetalization reaction of glycerol with acetone for selective solketal synthesis (biofuel derivative). Through systematic optimization of multiple reaction parameters, the most favorable conditions for solketal synthesis were identified. The ideal reaction conditions involved an 8:1 M ratio of acetone to glycerol (AC to GL), a 6 wt% catalyst loading, an 8-min reaction time, and a temperature of 60 °C. A significantly high surface area of 326.21 m2/g for the ZBC-SO 3 H nanocatalyst demonstrates its exceptional potential for catalytic applications. In addition, the plausible reaction pathway for selective solketal synthesis was suggested. The catalyst was reusable up to 6 reaction runs in the solketal synthesis, which remarks the high stability of the ZBC-SO 3 H. Further, the reusability of the ZBC-SO 3 H (remaining catalyst after 6 runs) was examined in the adsorption of methylene blue (MB) dye. This groundbreaking study showcases the exceptional performance of the ZBC-SO 3 H nanocatalyst in selective solketal production and its remarkable reusability in the adsorption of methylene blue dye. The outstanding results underscore the novelty and significance of this research endeavor. [Display omitted] [ABSTRACT FROM AUTHOR]

The dual bamboo and coconut waste-derived catalyst was utilized to enhance the esterification reaction between two incompressible reactants, (oleic acid and methanol), to increase the mass transfer, which further decreased the reaction time and energy. The comparison study of the sulfonated dual waste biochar (DWBS) with single biomass-derived catalysts, sulfonated bamboo biochar (BBS), and sulfonated coconut husk biochar (CHBS) shows that the DWBS catalyst efficiently produces biodiesel by esterification reaction under optimum conditions. The catalyst significantly reduces activation energy to a greater extent, with a value of 32.32 kJ/mol as compared to BBS and CHBS catalysts. The reusability study reveals that the DWBS catalyst is effective for up to six cycles, demonstrating the catalyst's remarkable stability. The results indicate that the DWBS catalyst could be used for biodiesel production with low catalyst loading and a high reaction rate. [Display omitted] [ABSTRACT FROM AUTHOR]

• This review highlights the recent advancement in the waste-derived materials. • Various characteristics and synthesis methods for novel materials are given in this review. • Waste-derived materials are cost-effective, efficient and environment-friendly. • The current development problems and future perspectives of waste-derived materials are pointed out. Human faces major problems regarding the environment. Although many materials are used to solve these problems, they are not so effective against them because they generate secondary pollution. Waste materials such as fly ash, biomass, red mud, and others material are used in various processes for effectively removing them. Also, the utilization of waste materials into valuable derivatives results in these materials' cost efficiency. Additionally, waste materials have several advanced properties like high surface area, high functional group, high adsorption capacity, etc. The efficiency of waste materials increases by incorporating nanoparticles, which are used for multifunctional applications. Nanoparticles may be stabilized and dispersed with the help of waste materials. In this review, (1) recent development in the waste-derived materials is discussed, (2) the properties and synthesis of waste materials are discussed, and (3) various process like adsorption, photodegradation, and advanced oxidation process (AOP) for environmental remediation are discussed. In conclusion, we have also provided future directions for the development of novel waste-based composite materials for efficient dealing with these kinds of problems. [Display omitted] [ABSTRACT FROM AUTHOR]