Effects of excessive impregnation, magnesium content, and pyrolysis temperature on MgO-coated watermelon rind biochar and its lead removal capacity

Abstract

MgO-coated watermelon rind biochar (MWRB) is a potentially highly-effective waste-derived material in environmental applications. This research aims to provide valuable insights into the optimization of the production of MWRB for superior environmental performance. It was found that the Mg content of the MWRB could be easily controlled by adjusting the Mg/feedstock mass ratio during excessive impregnation. The BET surface area was found to first increase and then decrease as the Mg content of the MWRB (produced at 600 °C) increased from 1.52% to 10.1%, with an optimal surface area of 293 m 2 /g observed at 2.51%. Similarly, an optimum pyrolysis temperature of 600°C was observed in the range of 400-800 °C for a maximum surface area of the MWRB at a fixed Mg/feedstock ratio of 0.48% (resulting in MWRBs with Mg contents of 1.89-2.51%). The Pb removal capacity of the MWRB (produced at 600°C) increased with increasing Mg content, with a greatest Pb removal capacity of 558 mg/g found for the MWRB with the highest Mg content (10.1%), an improvement of 208% over the 181 mg/g Pb removal capacity of unmodified WRB produced at 600°C. The Pb removal capacity of the MWRB (produced with 1.89-2.51% Mg) was also discovered to increase from 81.7 mg/g (at 400 °C) to 742 mg/g (at 700°C), before dropping to 368 mg/g at 800 °C. These findings suggest that the MWRB can be more efficiently utilized in soil and water remediation by optimizing its synthesis conditions.

Biochar for sustainable soil management

“…Biochar has been found to be effective in immobilizing heavy metals including Cd, Pb, etc (Jing et al., 2020; O'Connor et al., 2018). Various modification strategies have been explored to strengthen the immobilization capability of biochar made from a variety of feedstock (Wang et al., 2020; Zhang, Hou, et al, 2020). Besides the remediation of heavy metal contaminated soil, biochar has also been explored to address various types of degraded land.…”

Sustainable soil use and management: An interdisciplinary and systematic approach

“…Traditionally, remediation practitioners focused on either physical cleanup methods, such as soil excavation and disposal at landfill (Qi et al, 2020), or chemical treatment methods, such as in situ chemical oxidation (O'Connor et al, 2018a). In recent years, nature-based solutions, such as phytoremediation and green stabilization, have gained attention among the scientific research community (Wang et al, 2019b;Wang et al, 2020b;Zhang et al, 2020a). For example, microbial strains from unique natural environments are being harvested, cultured, and exploited to render economic and environmentally friendly solutions for soil decontamination (Atashgahi et al, 2018;Bunge et al, 2003).…”

Solvent-Free Synthesis of MgO-Modified Biochars for Phosphorus Removal from Wastewater

“…However, both surface area (S BET ) and V total were slightly reduced for 3MgO/BC-450-0.5, which was prepared with a higher Mg precursor-to-rice straw mass ratio. The pores in 3MgO/BC-450-0.5 were blocked by the inserted MgO particles, leading to a decrease in S BET compared with that of 2MgO/BC-450-0.5 (Table 1) [36,37]. The average dimeter (D BJH ) decreased after mixing ball-milling of biochar and Mg precursor (Table 1).…”