Adsorption Properties of Thermally Treated Rice Husk for Removal of Sulfamethazine Antibiotic from Pharmaceutical Wastewater

Equilibrium sorption of the Thermally Treated Rice Husk (TTRH) for Sulfamethazine (SMT) adsorption was studied. The Physico-chemical properties of the modified rice husk were determined. The equilibrium sorption data were fitted into Langmuir, Freundlich and Dubinin–Radushkevich isotherms. Of the three adsorption isotherm, the R2 value of Langmuir isotherm model was the highest. Also compared to other isotherms the AARE coefficient for the Langmuir isotherm is low, which indicates favorable sorption. The maximum monolayer coverage (qm) from Langmuir isotherm model was determined to be 19.11 mg/g, the separation factor indicating a favorable sorption experiment is 0.446. Also from Freundlich Isotherm model, the sorption intensity (n) which indicates favorable sorption and the correlation value are 1.84 and 3.79 respectively. The mean free energy was estimated from Dubinin–Radushkevich isotherm model to be 9.18 KJ/mol which clearly proved that the adsorption experiment followed a physical process.

Acetic acid adsorption onto activated carbon derived from pods of Acacia nilotica var astringens (Sunt tree) by chemical activation with ZnCl2

The purpose of this study is to prepare and investigate the adsorption behavior of acetic acid onto two samples of activated carbon prepared from Acacia nilotica var astringens, Sunt tree,( SUNT-C1 and SUNT-C2). Applicability Langmuir, Freundlich, Temkin and Dubinin-Radushkevitch models of adsorptions isotherm have been tested, while acetic acid initial concentration varied between (0.010 – 0.300) mol/dm3. A comparative study of adsorption capacities of these samples was performed. The obtained data were compared and fitted well with the four models; there exist a correlation between physico- chemical properties of the activated carbons and the sorption processes. The maximum monolayer coverage (Qo) from Langmuir isotherm model was determined to be 1.016mg/g. Also from Freundlich Isotherm model, the sorption intensity (n) which indicates favourable sorption and the correlation value are 1.11 and 1.09 respectively.

Effect of Organic and Mineral Soil Fractions on Sorption Behaviour of Chlorophenol and Triazine Micropollutants

Effect of Organic and Mineral Soil Fractions on Sorption Behaviour of Chlorophenol and Triazine MicropollutantsThis article compares the sorption behaviour of 2,4,6-trichlorophenol, 2,3,4,6-tetrachlorophenol, pentachlorophenol, chlorotriazine atrazine, methylthiotriazine ametryn, methoxytriazine atratone, hydroxyatrazine, and didelakylated atrazine in a topsoil and an aquifer sediment before and after removal of sorbent organic matter and in humic acid. Freundlich isotherm coefficients Kf and 1/n and free energy change (δG°) were calculated for all compounds in all sorbents. According to sorbent pH values, chlorophenolate anions and uncharged triazine species dominated in all sorption experiments with topsoil and aquifer sediment. In experiments with humic acid, chlorophenols, atrazine, and didealkylated atrazine existed almost completely as neutral species, whereas protonated species dominated for hydroxyatrazine, atratone, and ametryn. In addition to a hydrophobic partition, sorption of all compounds in native soil and sediment sorbents includes specific, more polar interactions, which greatly depend on sorbate acidity/basicity, specific properties of the sorbent organic matter and of mineral surface, as well as on the system pH. A significantly greater sorption intensity of all compounds in "organic-free" than in the native aquifer sediment confirmed the importance and possible dominance of mineral surface in the sorption process. Sorption intensity of chlorophenol and triazine compounds in humic acid was closely related to compound hydrophobicity. Greater sorption of almost completely protonated hydroxyatrazine than of the more hydropohobic but uncharged atrazine indicated different humic acid reaction sites for two compounds and consequently different sorption mechanisms.

Influence of compost characteristics on heavy metal sorption from synthetic stormwater

This paper has the aim to assess the ability of garden derived compost to remove dissolved heavy metal contaminants typically found in stormwater. Compost was found to have excellent chemical and physical properties for the sorption of dissolved metal ions (Cu2+, Pb2+ and Zn2+). Batch sorption data were used to determine the sorption efficiency of Cu (93%), Zn (88%) and Pb (97%) by compost. The relative sorption affinity of these metals by compost is found to be in the order of Pb2+ >Cu2+∼ Zn2+. The effect of different particle size fractions of compost upon the sorption of Cu was also investigated. Sorption conformed to the linear form of the Freundlich isotherm and can be considered favourable because the sorption intensity values obtained in this study are between 0.1 and 1. Compost with a smaller particle size fraction has larger surface areas and greater sorption than the larger particle size fraction. Compost derived from garden waste is efficient for removal of heavy metals from wastewater or treating water for industries.