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Optimization and kinetics analysis of xanthan gum wastewater treatment with pyrolusite



This article deals with treating actual xanthan gum wastewater with pyrolusite by Response Surface Methodology (RSM). The effects of solid-to-liquid ratio, sulfuric acid concentration, reaction time, and temperature on COD removal efficiency of xanthan gum wastewater were studied with laboratory bench-scale experiments. The results showed that the maximum removal rate of COD was 65.63% on the optimum treatment conditions (temperature of 87.3°C, sulfuric acid concentration of 88.15 g/L, solid-to-liquid ratio of 9.57%, and time of 3.49 h). Temperature, reaction time, sulfuric acid concentration and solid-to-liquid ratio were four important factors which should be well controlled to guarantee high COD removal rate. The activation energy was determined to be 36.08 kJ/mol and the reaction orders with respect to xanthan gum wastewater and H+ concentration was −2.020 and 1.097, respectively. The kinetics analysis showed that the reaction was controlled by both chemical reaction on particle surface and diffusion across the product layer. This study would offer a fundamental method for xanthan gum wastewater treatment with flexibility, simplicity, and high efficiency. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 430–436, 2014