Efficient Removal of Pb(II) from Aqueous Medium Using Chemically Modified Silica Monolith

The adsorptive removal of lead (II) from aqueous medium was carried out by chemically modified silica monolith particles. Porous silica monolith particles were prepared by the sol-gel method and their surface modification was carried out using trimethoxy silyl propyl urea (TSPU) to prepare inorganic–organic hybrid adsorbent. The resultant adsorbent was evaluated for the removal of lead (Pb) from aqueous medium. The effect of pH, adsorbent dose, metal ion concentration and adsorption time was determined. It was found that the optimum conditions for adsorption of lead (Pb) were pH 5, adsorbent dose of 0.4 g/L, Pb(II) ions concentration of 500 mg/L and adsorption time of 1 h. The adsorbent chemically modified SM was characterized by scanning electron microscopy (SEM), BET/BJH and thermo gravimetric analysis (TGA). The percent adsorption of Pb(II) onto chemically modified silica monolith particles was 98%. An isotherm study showed that the adsorption data of Pb(II) onto chemically modified SM was fully fitted with the Freundlich and Langmuir isotherm models. It was found from kinetic study that the adsorption of Pb(II) followed a pseudo second-order model. Moreover, thermodynamic study suggests that the adsorption of Pb(II) is spontaneous and exothermic. The adsorption capacity of chemically modified SM for Pb(II) ions was 792 mg/g which is quite high as compared to the traditional adsorbents. The adsorbent chemically modified SM was regenerated, used again three times for the adsorption of Pb(II) ions and it was found that the adsorption capacity of the regenerated adsorbent was only dropped by 7%. Due to high adsorption capacity chemically modified silica monolith particles could be used as an effective adsorbent for the removal of heavy metals from wastewater.

Removal of Iron From Produced Water Using Silica Adsorbent Material

The removal of Iron from produced water using adsorbent materials is taking a space of attention from the perspective of researchers. In this work, the characterization of chemically modified silica used as Iron ions adsorbent using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), laser granularity instrument was performed. The point of zero charge (PZC) of modified silica was determined using titration method. Different parameters were used to better approach Iron removal. These parameters are 0.2 and 0.4 mg/l modified silica adsorbent dose, 30-180 min adsorption time and pH values of 4-10. The results showed that modified silica exhibited higher removal efficiency of Iron due to its surface characteristics. The results also showed that at 60 min adsorption time and pH 7, the maximum Iron removal efficiency with 99.99% and 99.98% was obtained using modified silica dose of 0.4 mg/l and 0.2 mg/l, respectively.

Chemically Modified Silica Materials as Model Systems for the Characterization of Water-Surface Interactions

A series of novel functionalized mesoporous silica-based materials with well-defined pore diameters, surface functionalization and surface morphology is synthesized by co-condensation or grafting techniques and characterized by solid-state NMR spectroscopy, DNP enhanced solid state-NMR and thermodynamic techniques. These materials are employed as host-systems for small-guest molecules like water, small alcohols, carbonic acids, small aromatic molecules, binary mixtures and others. The phase-behavior of these confined guests is studied by combinations of one dimensional solid-state NMR techniques (1H MAS,2H-line shape analysis,13C CPMAS) and two-dimensional correlation experiments like1H-29Si- solid-state HETCOR.