The efficiency of Pterocarpus Anglolensis sawdust, an abundantly available waste product of the timber industry, capacity as an adsorbent for mercury was investigated. A series of batch experiments was carried out with experimental conditions of metal concentration, adsorbent concentration, pH, and contact time being changed. The concentration of the metal ion was deduced using spectrophotometric means. The Adsorption efficiency was found to be pH-dependent with pH 4 being the optimum. 90 minutes was found to be the equilibrium time with particle size range 90-124 μ m being the most efficient. Maximum Adsorption of mercury was evaluated at 80. 33 %. The experimental data was best modeled by the Freundlich isotherm and Pseudo second-order kinetic models. The calculated Adsorption parameters are Kf = 0. 0002 L/mg, bF = 3. 0 and k2 = 0. 00016 g/μ g. min.

The removing of ferric ions (Fe3+) from aqueous solution using natural feldspar (NF) has been studied in a batch operation mode. The factors affecting of the sorption equilibrium, such as contact time, initial concentration of the ferric ions (Fe3+), feldspar dosage concentration and temperature, were investigated. The maximum removal is 93 % (approx.) using low-level concentration of Fe3+ions (30 mg L-1) and high dosage concentration (40 g L-1). The Adsorption equilibrium is achieved during the first 90 min. Freundlich model has successfully analyzed the equilibrium of isotherms with R 2 = 1. The Adsorption mechanism of aqueous ferric ion on NF follows Freundlich isotherm models (R 2 = 0.997). The capacity (K f) and intensity (1/n) of Freundlich Adsorption are 1.70 and 0.621, respectively. The results reveal that the Adsorption mechanism of ferric ion on NF is chemisorptions, heterogeneous multilayer and spontaneous in nature (DG = -19.778 kJ mol-1). Adsorption reaction kinetic models, such as pseudo-first order and pseudo-second order, and Adsorption diffusion model, such as Weber-Morris intraparticle diffusion model, have been used to describe the Adsorption rate and mechanism of the ferric ion onto NF surface. Adsorption of ferric ion on the NF has achieved Lagergren pseudo-second-order model (R 2 = 1.0 approx.) more than Lagergren pseudo-first-order model. The kinetic parameters, rate constant and sorption capacities have been calculated. The new information in this study suggests that NF could be used as a novel filtering materials for removing ferric ions from water.

In this study, a mesoporous silica nanostructure was synthesized and magnetized (Magnetic-SBA-15) and then its ability to remove reactive red 198 dye (RR198) from aqueous solution was investigated. The structure of produced adsorbent were evaluated by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). the effect of effective parameters on the Adsorption process such as pH, adsorbent dose, contact time, temperature and dye concentration were investigated and optimized. The optimum conditions for removal of reactive red 198 dye was pH =2, adsorbent dosage of 0. 4 g/l ,contact time of 60 minutes and temperature 25 ⁰C in 60 ppm of dye concentration. UV-vis spectrophotometer was used to determine the amount of residual dye in the solution. To determine the type of Adsorption isotherm, the Langmuir, Freundlich and dubinin-radushkevich equations of Adsorption isotherms were used. The results showed a good fit for the Langmuir Adsorption isotherm (R2 = 0.997 and RL = 0.275). According to the values obtained from thermodynamic parameters such as enthalpy (-15.346 kJ/mol) and Gibbs free energy, the removal of reactive red 198 dye by Magnetic-SBA-15 was exothermic and spontaneous.