Sorption of V and VI group metalloids (As, Sb, Te) on modified peat sorbents

The present work investigates arsenic, antimony and tellurium sorption using iron modified peat. The results were obtained using batch tests and the sorption was studied as a function of initial metalloid concentration, pH and sorption time, as well as the presence of competing substances. The obtained results indicate that modification of peat with Fe compounds significantly enhances the sorption capacity of the sorbents used for sorption of arsenic, antimony and tellurium. The optimal pH interval for the sorption of Sb(III) is 6.5–9 and for As(V) and Sb(V) – 3–6, while As(III) and tellurium sorption using Fe-modified peat is favourable in a wider interval of 3–9. The presence of competing ions as well as HA affect sorption of metalloids on Fe-modified peat. A minor impact on the reduction of metalloid sorption was detected in the presence of nitrate, sulphate, carbonate and tartrate ions, while in the presence of phosphate and HA the sorption ability of metalloids can be considerably reduced. The obtained results of kinetic experiments indicate that sorption of metalloids on Fe-modified peat mainly occurs relying on mechanisms of physical sorption processes.

Adsorption of Anticorrosion and Antiwear Additives on Axletree

Experimental investigation of adsorbent was conducted about the anti-corrosion additives on the surface of simulating axletree, testified the existence of physical sorption on the axletree surface through the molar consistency changes of anti-corrosion additives in lubricating oil before and after adsorbent experiments which represented by ultraviolet absorbance. Did adsorbing experiments using the cosmoline dashed with different content of anti-wear additives, found that anti-wear additives could affect the adsorbability between the axletree and anti-corrosion additives through ultraviolet absorbance measurements, the results reflect that the interacting sorption between the two additives on surface of axletree.

Sorption of Ammonium Ions onto Natural and Modified Egyptian Kaolinites: Kinetic and Equilibrium Studies

Thermally activated, acid-activated, and acid-leached of thermally activated kaolinites were prepared from the Egyptian ore. The physical and chemical properties were studied using N2 sorption at −196°C, FTIR, SEM, and the total surface acidity. The sorption of NH4+ ions on the investigated sorbents was controlled with the solution pH, sorbent dosage, and initial concentration of NH4+ solution. Kinetic and equilibrium NH4+ sorption at 30°C were employed. Four kinetic models were applied to the kinetic sorption data; pseudo-second-order, Elovich, and intraparticle diffusion models fitted well the kinetic data whereas pseudo-first-order model was less applicable. Elovich parameters refer to physical sorption type of NH4+ on nonuniform sites and the intraparticle diffusion controls the sorption of NH4+ by kaolinites to a small extent. The equilibrium sorption data followed Langmuir and D-R models; the negative value of ΔG indicates a spontaneous sorption and the mean sorption energy obtained shows also physical sorption. The sorption capacities of nonactivated and activated Egyptian kaolinites towards NH4+ sorption (10.87–45.45 mg·g−1) were good sorbents as compared with those uptaken by other clays reported in the literature and proved to be more active besides being less expensive and highly available.