Investigating the sorption behavior of cadmium from aqueous solution by potassium permanganate-modified biochar: quantify mechanism and evaluate the modification method

Abstract

In this work, a KMnO-modified-biochar-based composite material with manganese oxide produced at 600 °C was fabricated to investigate the sorption mechanism of Cd(II) and to comprehensively evaluate the effect of the modification on biochar properties. Cd(II) adsorption mechanisms were mainly controlled by interaction with minerals, complexation with oxygen-containing functional groups, and cation-π interaction. The sorption capacity was significantly reduced after a deash treatment of biochar, almost shrunk by 3 and 3.5 times for pristine biochar (PBC) and modified biochar (MBC). For deashed PBC, oxygen-containing functional groups were the main contributor toward Cd(II) adsorption while interaction with minerals was significantly compromised and became negligible. The sorption capacity was also apparently decreased after the deash treatment of MBC; however, for deashed MBC, interaction with minerals still was the main contributor to the sorption ability, which could be attributed to the mechanism of interaction of Cd(II) with loaded MnO on biochar. Cation-π interaction in MBC was notably enhanced compared to PBC due to the oxidation of KMnO on biomass. Also, sorption performance by oxygen-containing functional groups was also enhanced. Hence, the modification by KMnO has a significant effect on the Cd(II) sorption performance of biochar.

Activation of persulfate by manganese oxide-modified sludge-derived biochar to degrade Orange G in aqueous solution

“…The peak disappeared after the reaction, which indicates those functional groups also contributed to the PS activation reaction. Two peaks around 628-580 cm −1 that can be assigned to Mn-O appeared in Mn-SDBC, while such peaks were not found in SDBC and Mn-SDBC after reaction, which indicates that the manganese oxides were successfully loaded in the surface of SDBC and these oxides were dissolved into the solution during the experiment and cause Mn loss [18,21]. This result is well-correlated with the results of XRF.…”

“…As mentioned in Section 3.2, the final pH decreased to around 2.8. In this acidic condition, manganese oxides and other metal oxides that could serve as activation sites are more readily dissolute into the solution, and thus the degradation rate slowed down regardless of the excessive PS in solution, which leads to a lower removal efficiency in 720 min compared to higher dosage [18].…”

A sustainable biochar catalyst synergized with copper heteroatoms and CO2 for singlet oxygenation and electron transfer routes

“…60,61 The area ratios of the D peak to the G peak (AD/AG) and the sum of G, V, and V 1 peaks (AD/A(G1+V+V1)) of the CO2-pyrolyzed composites are greater than that produced in N2, suggesting that CO2 medium induced more fused aromatic rings and structural edge defects within the biochar matrix during pyrolysis. 23,62,63 This can be attributed to the enhanced dehydrogenation of organic matter (viz. Boudouard reaction: C + CO2 2CO; biomass biochar + tar + CnHm) at high temperature with CO2 purging, which could generate more vacancy and zigzag edges as structural-dimensional defects.…”

Enhancement of Cd(II) adsorption by rice straw biochar through oxidant and acid modifications

“…Cadmium (Cd) is a highly toxic heavy metal (Mohan and Singh 2002;Fan et al 2018), which is widely used in electroplating industry, chemical industry, electronic industry, and nuclear industry. Since the twentieth century, the production of Cd has been increasing year by year.…”