Biochar a Promising Strategy for Pesticide-Contaminated Soils

Abstract

Soil pesticide contamination induced by modern agriculture has become a serious global issue. Its uncontrolled and inefficient application is among the main reasons for their enrichment in plants and animals subsequently transferred to humans and providing a public health risk. Biochar as a renewable and economical carbonaceous material provides a natural solution for immobilizing pesticides and improving soil health. The biochar impact in agricultural contaminated soil is governed by various factors such as the physico-chemical properties of biochar, pyrolysis, soil conditions, and the application method, which can lead to significant gaps in the removal or mitigation of toxic substances. The current study summarizes the negative effects of pesticide use and the advantages of biochar according to other remediation techniques, succeeded by the mechanism and controlling factors on minimizing pesticide leaching and bioavailability in soil. In addition, the role of biochar on fundamental processes of adsorption, desorption, biodegradation, and leaching is discussed. Ultimately, the major future research regulation and key strategies that are fundamental for pesticide-contaminated soil remediation are proposed.

Biochar-Soil-Plant interactions: A cross talk for sustainable agriculture under changing climate

“…Biochar is stable and its great content of aromatic C that is harder to decompose than plant biomass is the basis of the C sequestration paybacks of biochar. The pyrolysis of plant biomass breaks the natural C cycle and realizes carbon sequestration through biochar storage in the soil (Cara et al, 2022). It is assessed that around six GtC/yr of carbon biomass is accessible for biochar creation worldwide if 10% of net primary production is utilized, from which 3 GtC/yr of biochar can be created (Pan et al, 2022).…”

Deashed Wheat-Straw Biochar as a Potential Superabsorbent for Pesticides

“…In general, pore filling induced by the large surface area of the biochar is postulated as the dominant adsorption mechanism for carbonaceous materials of H/C values below 0.5 [ 73 ]. Previously discussed changes in the atomic ratios of H/C and O/C resulting from the demineralization of the BC sample indicate an increase in biochar aromaticity, and at the same time may suggest a slight increase in the share of chemisorption in the binding of the tested phenoxyacetic acids in relation to physical sorption (van der Waals interactions, London forces) [ 11 ]. Increased SSA of BCd and pore unclogging may have compensated previously reduced ability of surface OH functional groups to form chemical bonds.…”

“…Many attempts have also been made to modulate the basic pyrolysis process parameters (input material, temperature, time) to obtain modified biochar [ 7 , 8 ]. The aim of that was to design a material with properties allowing for the retention of particular groups of pollutants, such as heavy metals [ 9 ], polycyclic aromatic hydrocarbons [ 10 ], pesticides [ 11 ], pharmaceuticals, or personal care products [ 12 ]. In subsequent studies, many chemical and physical activation methods of biomaterials (both on the pre-pyrolyzed biomass or pristine biochar produced) have been implemented to produce the biosorbent of the desired properties [ 13 , 14 , 15 ].…”

“…These mechanisms are mostly reversible, weak intermolecular physical interactions [ 33 ]. At the consecutive stage, chemisorption may play a role through covalent bonding or complex formation, which are irreversible monolayer chemical interactions [ 11 ]. Therefore, pesticide sorption on biochar matrix is often the result of synergistic mechanisms, depending on physicochemical attributes of the sorbent and agrochemical properties.…”

Adsorption-Desorption Behavior and Pesticide Bioavailability of Biochar in Soil

“…As per some investigations, biochar has a composite structure composed of amorphous organic matter, inorganic minerals, and crystalline organic matter (20). The surface is covered by inorganic minerals with a high cation exchange capacity, similar to clay minerals, and the concentration of free OH-in the solu-tion rises, as does the pH of the system (21), which might hasten the hydrolysis of organophosphorus pesticides (22) and carbamate pesticides (23). If biochar was aged for two years, the immobilization impact on triazine pesticides (simazine) did not alter significantly, indicating that biochar use is ongoing (24).…”