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The kinetics and optimization of the decoloration of an active commercial dye, argazol blue BFBR (ABB), by a heterogeneous Fenton-like reaction catalyzed by natural schorl were investigated in this study. The kinetic investigations revealed that the first-order kinetic model was more favorable to describe the decoloration of ABB under different reaction conditions than the second-order and Behnajady-Modirshahla-Ghanbery models. The relationship between the reaction rate constant k and reaction temperature T followed the Arrhenius Equation, with an apparent activation energy E a of 51.31 kJ·mol -1 . The central composite design under the response surface methodology was employed for the experimental design and optimization of the ABB decoloration process. The significance of a second order polynomial model for predicting the optimal values of ABB decoloration was evaluated by the analysis of variance and 3D response surface plots for the interactions between the two variables were constructed. Then, the optimum conditions were determined.

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Activation of peroxymonosulfate (PMS) by metal-doped C-N-based materials have been used extensively for pollutant degradation, but usually suffers from low efficiency and stability due to relatively low N coordinate sites,...

A cationic dye, Rhodamine B (RhB), could be efficiently discolored by heterogeneous Fenton-like reaction catalyzed by natural schorl. In this work, with the main goal of the optimization for RhB discoloration, central composite design under the response surface methodology (RSM) was employed for the experiment design and process optimization. The significance of a second-order polynomial model for predicting the optimal values of RhB discoloration was evaluated by the analysis of variance and 3D response surface and counter plots for the interactions between two variables were constructed. The Pareto graphic analysis of the discoloration process indicated that, among all the variables, solution pH (X 3, 47.95 %) and H2O2 concentration (X 1, 24.39 %) had the largest influences on the heterogeneous Fenton-like discoloration of RhB. Based on the model prediction, the optimum conditions for RhB discoloration were determined to be 45 mM H2O2 concentration, 2.5 g/L schorl dosage, solution pH 2, and 110 min reaction time, with the maximum RhB discoloration ratio of 98.86 %. The corresponding experimental value of RhB discoloration ratio under the optimum conditions was determined as 99.31 %, which is very close to the optimized one, implying that RSM is a powerful and satisfactory strategy for the process optimization.

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As a carbon-rich material produced by pyrolysis of biomass, biochar features low cost, large specific surface area, and widely available feedstocks based on the functional diversity and environmental-friendly properties, it has received increasing attention in the fields of pollutant removal due to three win–win effects of water remediation, carbon sequestration and reutilization of wastes. To design excellent biochar-based catalysts for environmental applications, one must understand recent advances in the catalysts for contaminant removal. This review focuses on the current application of biochar-based catalysts in redox systems, Fenton-like systems, sonocatalytic systems and photocatalytic systems. Besides in-depth discussion in effects of preparation conditions on physicochemical characteristics of biochars, the review supplements new preparation technologies of biochar and biochar-based catalysts. Most importantly, the advantages/shortcomings, catalysis mechanisms, as well as the pollutant removal ability of different types of biochar-based catalysts are discussed. The environmental risks of the catalyst applications are also elaborated on. Future research on biochar-based catalyst production and its environmental applications is discussed. The review provides a good overview of the current advances of biochar-based catalysts in pollutant control and the futureresearch directions. Graphical Abstract