Influence of organic carbon and metal oxide phases on sorption of 2,4,6-trichlorobenzoic acid under oxic and anoxic conditions

• Published in: Environmental monitoring and assessment Vol. 187; no. 1; pp. 4170 - 15
• Main Authors: Ololade, Isaac Ayodele, Oladoja, Nurudeen Abiola, Alomaja, Folasade, Ololade, Oluwaranti Olubunmi, Olaseni, Esan O., Oloye, Femi Francis, Adelagun, Ruth O. A.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.01.2015; Springer Nature B.V
• Subjects: Acids; Adsorption; Anoxic conditions; Atmospheric Protection/Air Quality Control/Air Pollution; Carbon; Carbon - analysis; Carbon - chemistry; Chemicals; Chlorobenzoates - analysis; Chlorobenzoates - chemistry; Dissolution; Dissolved organic carbon; Earth and Environmental Science; Ecology; Ecotoxicology; Electrode potentials; Environment; Environmental conditions; Environmental Management; Environmental monitoring; Floods; Herbicides; Herbicides - analysis; Herbicides - chemistry; Kinetics; Mathematical models; Metabolites; Metal oxides; Metals - analysis; Metals - chemistry; Models, Chemical; Monitoring/Environmental Analysis; Organic matter; Oxidation-Reduction; Oxides - chemistry; PCB; Polychlorinated biphenyls; Redox potential; Soil (material); Soil - chemistry; Soil Pollutants - analysis; Sorption; Surface area; Surface chemistry; Xenobiotics; Oxic and anoxic; Kinetics; Redox potential; Adsorption; 2,4,6-Trichlorobenzoic acid
• ISSN: 0167-6369; 1573-2959
• DOI: 10.1007/s10661-014-4170-2

Chlorobenzoic acids represent crucial recalcitrant metabolites in the environment; thus, the influence of soil components on the sorption of 2,4,6-trichlorobenzoic acid (TCB) under oxic and anoxic conditions was studied. The surficial physiognomies of untreated and isolated soil samples were studied using FTIR, XRD, specific surface area, and PZC determination. The roles of redox potential, dissolved organic carbon (DOC), and pH, particularly under anoxic condition, were appraised. Batch equilibrium adsorption studies on soils of variable Fe/Mn oxides and organic carbon showed that adsorption was low across all components (log K oc  = 0.82–3.10 Lg −1 ). The sorption of 2,4,6-TCB was well described by the pseudo second-order kinetic model. The fluctuation of both redox potential and pH during anoxic experiment had a negative impact on the sorption, partitioning, and the oxidation of organic matter. Linear relationships were observed for K d with both soil total organic carbon (TOC) and surface area (SA). The results showed the existence of DOC-mediated sorption of 2,4,6-TCB which seems to be enhanced at lower pH. The reductive dissolution, particularly of iron compounds, possibly impeded sorption of 2,4,6-TCB under anoxic condition. It could be inferred that habitats dominated by fluctuating oxygen concentrations are best suited for the development of environmental conditions capable of mineralizing 2,4,6-TCB and similar xenobiotics.