Modification of sodium aluminum silicate hydrate by thioglycolic acid as a new composite capable of removing and preconcentrating Pb(II), Cu(II), and Zn(II) ions from food and water samples

Abstract

In this paper, sodium aluminum silicate hydrate was synthesized using rice husk as a silicon source and scrap aluminum cans as an aluminum source. Afterward, with the aid of microwave heating, a composite of sodium aluminum silicate hydrate and (3-aminopropyl)trimethoxysilane was facilely synthesized then modified by thioglycolic acid to produce a new composite. Besides, characterization of the synthesized composite was carried out using XRD, FT-IR, TEM, CHN elemental analyzer, nitrogen gas sorption analyzer, and SEM. The XRD pattern of the produced composite shows that there is a halo at 2θ = 25.0°, which means that there is a crystalline structure that is combined with an amorphous background. The SEM and TEM studies indicate that the synthesized composite has a structure similar to cotton. The synthesized composite was utilized for the efficient removal and preconcentration of Pb(II), Cu(II), and Zn(II) ions from food and water samples prior to determination by flame atomic absorption spectrometry. The produced composite has a maximum adsorption capacity of 185.53, 168.92, and 125.94 mg/g for Pb(II), Cu(II), and Zn(II) ions, respectively. The recovery findings demonstrate that the process is accurate, adaptable, and resulted in quantitative separation (greater than95 percent). Furthermore, the % RSD was less than 3.5 percent, indicating good reproducibility. The Langmuir isotherm and pseudo-second-order model fit the experimental results well. The thermodynamic studies established that the adsorption process is spontaneous, chemical, and exothermic. The produced composite was successfully regenerated and used multiple times to remove the metal ions under investigation from aqueous solutions.