Huang et al.  reported a stimulating effect of low molecular weight selleck chemicals Carfilzomib organic acids for Cd and Pb adsorption by goethite and montmorillonite, but only at low concentrations. At higher concentrations of these acids, decreased heavy metal adsorption was recorded. While citric and tartaric acids enhanced desorption of Cu in soil, oxalic acid was effective in desorption of Cu and Cd . The mechanism of desorption was explained as competition in complexation, adsorption, and precipitation. Gao et al.  reported desorption of Cd and Cu by citric and tartaric acids, especially at higher concentrations. Low concentrations of these acids inhibited desorption.Organic acids appeared to be efficient in the release of 137Cs from contaminated soils, efficiency being in the order citric > tartaric > oxalic > succinic > acetic acid .
Desorption occurs in two phases: fast and slow. The fast stage of desorption corresponds with the interaction of organic acids with the surface of clay minerals, whereas the slow stage (occurring over a much longer period) is attributed to inter- and intraparticle diffusion. Debela et al.  reported the release of Pb from pyromorphite [Pb5(PO4)3Cl] by citric, malic, acetic, and oxalic acids. Interestingly, low concentrations of organic acids may increase adsorption of heavy metals in soil .2.2. Cyclic and Aromatic Organic Acids in SoilCyclic and aromatic organic acids play a range of roles in soils, including allelopathic interactions, inhibition of microbial growth, and weathering of minerals [78, 79].
Some aromatic acids in soil solution may also be used to distinguish between vegetation types in forests . Asao et al.  reported that benzoic, m- and p-hydroxybenzoic, vanillic, and adipic acids inhibited plant growth. Of these, benzoic acid was the strongest inhibitor. Ferulic acid is released from plant roots and from decomposition of soil organic matter and may be involved in allelopathic interactions. Caspersen et al.  reported the presence of bacteria in commercial hydroponic Lactuca sativa L. culture which were able to ameliorate the toxic effects of ferulic acid.Aromatic acids (salicylic and phthalic) are adsorbed by soils of different charges, and the adsorption of these acids differs significantly according to the soil tested. Adsorption of aromatic and aliphatic acids decreased the zeta potential of soils and oxides [81, 82].
Adsorption of salicylate in soil appeared to be significantly lower compared to citrate (Freundlich constant for adsorption KF 0.499 versus 0.107) . Adsorption of gallic acid was not influenced by soil depth or land use . Batimastat Gallic acid decreased the amount of total inorganic nitrogen extractable from soil by KCl and increased solubility of Ca and Mn through formation of metal-gallic acid complexes and redox reactions.