A critical review of sustainable application of biochar for green remediation: Research uncertainty and future directions.

Biochar, a carbon-rich material produced from the pyrolysis of organic biomass, has gained significant attention as a potential solution for sustainable green remediation practices. Several studies analyze biomass-derived biochar techniques and environmental applications, but comprehensive assessments of biochar limitations, uncertainty, and future research directions still need to be improved. This critical review aims to present a comprehensive analysis of biochar's efficacy in environmental applications, including soil, water, and air, by sequentially addressing its preparation, application, and associated challenges.

Remediation of phenol contaminated soil using persulfate activated by ball-milled colloidal activated carbon.

The degradation of phenolic compounds through persulfate (PS) activation is a valuable approach for soil/groundwater remediation. Several reports have been made related to PS activation and contaminant degradation using carbo-catalysts; however, there is no detailed study on soil remediation by colloidal activated carbon. This study demonstrates the phenol (PhOH) degradation efficiency in spiked and field-contaminated soils by a novel and low-cost ball-milled colloidal activated carbon (CAC) catalyst.

Colloidal activated carbon as a highly efficient bifunctional catalyst for phenol degradation.

A preparation of colloidal activated carbon (CAC) for phenol remediation from groundwater was introduced. The CAC prepared by a simple pulverization technique was an excellent metal-free catalyst for persulfate (PS) activation due to high contact surface area. The removal efficiency of phenol in the PS/CAC system (~100%) was higher than that in the PS/activated carbon (AC) system (90.

Removal of sulfadiazine and ciprofloxacin by clays and manganese oxides: Coupled sorption-oxidation kinetic model.

Sorption onto clays (montmorillonite and kaolinite), oxidation and sorption by manganese oxides (synthesized MnO and natural MnO), and coupled sorption-oxidation experiments were conducted for the removal of antibiotics sulfadiazine (SDZ) and ciprofloxacin (CIP) at pH 5 and 8. Individual sorption and oxidation modelling were carried out using the first-order kinetic model. A coupled sorption-oxidation kinetic model was developed to predict the simultaneous sorption and oxidation process.

Oxidative removal of sulfadiazine using synthetic and natural manganese dioxides.

Studies on oxidation kinetics of sulfadiazine (SDZ) using δ-MnO (birnessite) and natural MnO are limited. Reaction order at different SDZ speciation was determined based on the effects of initial H, MnO and SDZ concentrations using initial rate method, which would be useful to determine the optimum pH and MnO concentration. Birnessite and natural MnO with different physico-chemical properties such as BET surface area, pH, d-spacing, and crystal size similarly showed good efficiencies in oxidizing neutral SDZ (pH 5) and anionic SDZ (pH 8).

Sorption of antibiotics onto montmorillonite and kaolinite: competition modelling.

Antibiotic contaminants, which are generally present in bi-solute systems, can be competitively adsorbed onto clays. Single- and bi-solute sorptions of sulfadiazine (SDZ) and ciprofloxacin (CIP) onto montmorillonite and kaolinite were investigated at pH values of 5 and 8. Freundlich and Langmuir models were used and fit the experimental data well for single-solute sorption.