Organic micro-pollutant removal in liquid-phase using carbonized silk cotton hull

摘要

Phenolic compounds constitute one of the major pollutants in the modern world. Although many physical and chemical treatment technologies for their removal exist, most of them are economically not feasible. The present study was aimed at using silk cotton hull, a potent agricultural waste as an adsobent for removal of 2,4-dichlorophenol (2,4-DCP), which was used as a model phenolic compound. The process parameters were investigated and optimized conditions were determined. The equilibrium time was found to be 60 and 80 min for 10 and 20 mg/L and 100 min for 30 and 40 mg/L 2,4-DCP concentrations, respectively. Among the kinetic models applied, pseudo-second order model fitted well. The maximum adsorption capacity was 16.0 mg/g by Langmuir isotherm. Acidic pH was found favorable for the adsorption of 2,4-DCP. Studies on pH effect and desorption seemed to show that chemisorption played a major role in the adsorption process. In thermodynamic study, the change in entropy (△S 0) and heat of adsorption (△H0) of silk cotton hull carbon (SCHC) was estimated as 14.01 J/(mol·K) and 3.04 kJ/mol, respectively. SCHC as adsorbent for removal of 2,4-DCP from aqueous solution, is effective, inexpensive, indigenous, reusable, has low treatment time and is easily available in large quantities as waste there by significantly lowers the cost of wastewater treatment.