Preparation and adsorption behaviors of ethylene diamine tetraacetic acid modified zwitterionic hybrid materials

Abstract

Novel ethylene diamine tetraacetic acid (EDTA)-modified zwitterionic hybrid materials were prepared via a sol-gel process. Their adsorption performances for Pb 21 ions were examined. Fourier transform infrared spectroscopy confirmed the reaction products. Thermogravimetric analysis revealed that the thermal stability of these hybrid materials could reach 200 C. Differential scanning calorimetry measurement showed that the addition of titanium butoxide could impact the crystallization transformation of these materials. Field emission scanning electron microscopy images showed that EDTA modification induced a decrease in the particle size. Adsorption experiments demonstrated that the optimal initial pH was 5. Moreover, we observed that the adsorptions for Pb 21 ions followed the Lagergren pseudo-second-order kinetic model, intraparticle diffusion, and Langmuir isotherm model. In addition, we found that the maximal Langmuir constant was 0.86 mmol/g. The negative Gibbs free energy values suggested that Pb 21 adsorption onto these samples was spontaneous in nature. The desorption experiment indicated that these samples could be recovered with aqueous HCl solution as a desorbent. These results suggest that the synthesized EDTA-modified zwitterionic hybrid materials are promising adsorbents that could be used to separate and recover heavy-metal ions from polluted wastewater. V C 2013Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39801.

Enhanced removal of fluoride by tea waste supported hydrous aluminium oxide nanoparticles: anionic polyacrylamide mediated aluminium assembly and adsorption mechanism

“…45,46 In the present study, the Langmuir and Freundlich isotherm were tested. 45,46 In the present study, the Langmuir and Freundlich isotherm were tested.…”

“…45,46 In the present study, the Langmuir and Freundlich isotherm were tested. 46,47 Unlike the surface adsorption of the Langmuir model, the Freundlich isotherm (Eq 6) predicts the adsorption process occurs on a multilayer adsorption with the adsorption 35 energy decreasing with the surface coverage. 46,47 Unlike the surface adsorption of the Langmuir model, the Freundlich isotherm (Eq 6) predicts the adsorption process occurs on a multilayer adsorption with the adsorption 35 energy decreasing with the surface coverage.…”

“…The two adsorption isotherm models were plotted (line plot) with experimental data for Tea-Al and Tea-APAM-Al ( Fig. 46,48 The R L values studied at different C 0 were calculated (Table 4). 5d), with the isotherm parameters and regression coefficients (R 2 ) obtained from these models in Table 3.…”

“…Analysis of isotherm data is essential both for expressing the relationship between the concentration of sorbate and the applied adsorbent at constant temperature and for predicting the adsorption capacity of sorbent, which is a main parameter required for the design of an adsorption system. 45,46 In the present study, the Langmuir and Freundlich isotherm were tested. The Langmuir model (eqn ( 5)) is probably the most widely applied adsorption equation and is based on monolayer adsorption with uniform energies of adsorption onto the active reaction sites of the adsorbent.…”

“…The Langmuir model (eqn ( 5)) is probably the most widely applied adsorption equation and is based on monolayer adsorption with uniform energies of adsorption onto the active reaction sites of the adsorbent. 46,47 Unlike the surface adsorption of the Langmuir model, the Freundlich isotherm (eqn ( 6)) predicts the adsorption process occurs on a multilayer adsorption with the adsorption energy decreasing with the surface coverage. 19,47 Langmuir isotherm models :…”