Analysis of the Degradation of OCPs Contaminated Soil by the BC/nZVI Combined with Indigenous Microorganisms

Abstract

Organochlorine pesticides (OCPs) were typical persistent organic pollutants that posed great hazards and high risks in soil. In this study, a peanut shell biochar-loaded nano zero-valent iron (BC/nZVI) material was prepared in combination with soil indigenous microorganisms to enhance the degradation of α-hexachlorocyclohexane(α-HCH) and γ-hexachlorocyclohexane(γ-HCH) in water and soil. The effects of BC/nZVI on indigenous microorganisms in soil were investigated based on the changes in redox potential and dehydrogenase activity in the soil. The results showed as follows: (1) The specific surface area of peanut shell biochar loaded with nano-zero-valent iron was large, and the nano-zero-valent iron particles were evenly distributed on the peanut shell biochar; (2) peanut shell BC/nZVI had a good degradation effect on α-HCH and γ-HCH in water, with degradation rates of 64.18% for α-HCH and 91.87% for γ-HCH in 24 h; (3) peanut shell BC/nZVI also had a good degradation effect on α-HCH and γ-HCH in soil, and the degradation rates of α-HCH and γ-HCH in the 1% BC/nZVI reached 55.2% and 85.4%, second only to 1% zero-valent iron. The degradation rate was the fastest from 0 to 7 days, while the soil oxidation-reduction potential (ORP) increased sharply. (4) The addition of BC/nZVI to the soil resulted in a significant increase in dehydrogenase activity, which further promoted the degradation of HCHs; the amount of HCHs degradation was significantly negatively correlated with dehydrogenase activity. This study provides a remediation strategy for HCH-contaminated sites, reducing the human health risk of HCHs in the soil while helping to improve the soil and increase the activity of soil microorganisms.

Exploring the Impact of Surface Functionalization on the Reaction, Magnetophoretic, and Collective Transport Behavior of Nanoscale Zerovalent Iron

“…However, the primary goal of this section was to evaluate the feasibility of magnetic capture in reducing the nanoparticle transport distance after the reaction. Our motivation stems from the aspiration to develop an environmental cleaning technology by using nZVI as a nanoagent for degradation of pesticides and herbicides in soil. , We fully acknowledged that implementing magnetic capture in the field, particularly for large-scale in situ applications, presents significant challenges. Given the potential to track the lateral subsurface water flow, we envisage the possibility to capture the nZVI in the water stream from agriculture areas before it reaches the nearby water bodies.…”

Environmental remediation approaches by nanoscale zero valent iron (nZVI) based on its reductivity: a review

“…146 Li et al suggested that the addition of nZVI can signicantly increase the dehydrogenase activity of indigenous microorganisms in soil, and thus promote the removal of organochlorine pesticides. 147 The addition of nZVI in anaerobic/anoxic/aerobic membrane bio-reactor can provide electrons for the denitrication, thus enhancing the reduction of nitrate. 148 Similarly, Zhang et al adopted biochar-supported nZVI in the cathodic removal of nitrated in a bioelectrochemical system to enhance the reduction of nitrate to NH 4 + .…”

“… 146 Li et al suggested that the addition of nZVI can significantly increase the dehydrogenase activity of indigenous microorganisms in soil, and thus promote the removal of organochlorine pesticides. 147 …”

Bibliometric analysis of scientific productions related to the use of the word pesticide and associated terms

“…This state is the first concerning indigenous in the Center-West region and the second in the self-declared indigenous population throughout the country (IBGE, 2012). Some studies address the relationship between pesticides and indigenous (LI et al, 2023;SHANKER et al, 2023;ZHU et al, 2023).…”