Abstract
A highly efficient reduction process of Cr (VI) with biochar was conducted in this paper. The results showed that nearly 100% Cr (VI) was reduced at selected reaction conditions: Dosage of biochar at m (C)/m(Cr) = 3.0, reaction temperature of 90 °C, reaction time of60 min, and concentration of H2SO4 of 20 g/L. The reduction kinetics analysis demonstrated that the reduction of Cr (VI) fitted well with the pseudo-first-order model and the apparent activation energy was calculated to be 40.24 kJ/mol. Response surface methodology confirmed that all of the experimental parameters had a positive effect on the reduction of Cr (VI). The influence of each parameter on the reduction process followed the order: Dosage of biochar>concentration of H2SO4>reaction temperature >reaction time. This paper provides a versatile strategy for the treatment of wastewater containing Cr (VI) and shows a bright tomorrow for wastewater treatment.
Highlights
IntroductionPhotocatalysis and nanotechnology have been developed for the treatment of wastewater and show great performance [14,15]
The reduction process of Cr (VI) with oxalic acid with and without Mn (II) has been investigated and the results showed that Cr (VI) could not be reduced in an oxalic acid solution or an Mn (II) solution, while nearly 99% of Cr (VI) reduced to Cr (III) in an oxalic acid solution mixed with Mn (II)
The dosage of biochar and the concentration of H2 SO4 had the greatest influence on the reduction process
Summary
Photocatalysis and nanotechnology have been developed for the treatment of wastewater and show great performance [14,15]. Problems such as large-scale application, secondary pollution, and high cost remain. It was concluded that Mn (II) can catalyze the reduction process of Cr (VI) with oxalic acid. The impact of the experimental parameters, including the dosage of biochar, reaction temperature, reaction time, and concentration of H2 SO4 , on the reduction process were investigated.
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