Mespilus germanica (MG) and Tribulus terrestris (TT) Used as Biosorbents for Lead Removal from Aqueous Solutions: Adsorption Kinetics and Mechanisms

Abstract

Today, most countries around the globe are facing water resources restrictions, and it is predicted freshwater resources will be more valuable than oil wells in the next century. In the present study, the ability of lead removal using both powders of Mespilus germanica (MG) and Tribulus terrestris (TT) seeds and optimization of the adsorption process have been investigated. Four main parameters were selected for experimental design, namely, pH, time of contact, the ratio of adsorbent to solution volume, and initial concentration of lead in solution, and the optimization of effective parameters on lead adsorption was performed based on central composite design (CCD) under response surface methodology (RSM). According to the statistical results, the proposed model for MG and TT is confirmed with 0.95 and 0.96 correlation coefficient and 0.92 and 0.94 adjusted correlation coefficient, respectively. The results of parameter optimization also showed that both adsorbents have the acceptable ability to adsorb lead from aqueous solutions. Under the optimum conditions with the initial lead concentration of 10 mg/l, MG powder had better performance in lead adsorption of 96.04%, and TT powder also had an acceptive performance of 93.20%. Moreover, the MG and TT adsorbents have the most accordance with the Freundlich and D-R isotherms, respectively.

Optimization by Box–Behnken Design and Synthesis of Magnetite Nanoparticles for Removal of the Antibiotic from an Aqueous Phase

“…Scattering was obtained using Cu-K α radiation ( λ = 1.5406 λ ) in the range of 10 ° < 2 θ ° < 80 ° with steps of 0.02° and an achievement time of 1.0 s in steps. As shown in Figure 2, phase analysis results for magnetite Fe 3 O 4 particles have reasonably good compatibility between the peaks that become seen in the sample with the literature [51–53].…”

“…In this study, FT-IR was used to investigate the chemical bonds and levels of nanoparticles and the interactions that occurred at these levels during adsorption on the Fe 3 O 4 surface [40]. The FT-IR spectra of Fe 3 O 4 nanoparticles in the range bands at 400 cm -1 to 4000 cm -1 have been prepared and indicate that in this spectrum the func-tional groups in the frequency of 572 cm -1 which are related to the formation of the band the Fe-O and generally peak wavelength of bands 572 cm -1 , 1622 cm -1 , and 3420 cm -1 attributed to the tensile and flexural vibration of bond O-Fe, absorption band C=C, and the O-H bond in water adsorption (or carboxylic groups), respectively [52][53][54][55][56]. In this regard, the size of Fe 3 O 4 particles decreases to the nanoscale, the constant bond strength will increase, as a large number of bonds of surface atoms are broken as a result of the rearrangement of unstable electrons on the particle surface.…”