Saw-sedge Cladium mariscus as a functional low-cost adsorbent for effective removal of 2,4-dichlorophenoxyacetic acid from aqueous systems.

For the first time in the published literature, a study is described concerning the use of the saw-sedge Cladium mariscus ( C. mariscus) for adsorption of 2,4-dichlorophenoxyacetic acid (2,4-D) from aqueous systems. Among the experiments carried out, the elemental composition of C. mariscus was determined (C = 48.0 %, H = 7.1 %, N = 0.95 %, S = 0.4 %), FTIR spectroscopic analysis was performed to confirm the chemical structure of the adsorbent, and porous structure parameters were measured: BET surface area ( A = 0.6 m/g), total pore volume ( V = 0.001 cm/g) and average pore size ( S = 6.6 nm). It was shown that the effectiveness of removal of 2,4-D from aqueous systems using C. mariscus depends on parameters of the process: contact time, system pH, mass of sorbent, and temperature. Maximum adsorption was attained for a solution at pH = 3. Further increase in the alkalinity of the tested systems led to a reduction in the effectiveness of the process. The kinetic of adsorption of 2,4-D by C. mariscus was also determined, and thermodynamic aspects were investigated. The experimental data obtained correspond to a pseudo-second-order kinetic model of type 1. Additionally the negative values obtained for Δ Hº indicate that the process is exothermic, and the negative values of Δ Gº show it to be spontaneous. As the temperature of the system increases the spontaneity of adsorption is reduced, in accordance with the exothermic nature of the process. [ABSTRACT FROM AUTHOR]