Carbon Nanotubes Hybrid Hydrogels for Environmental Remediation: Evaluation of Adsorption Efficiency under Electric Field

Abstract

The performance of Carbon Nanotubes hybrid hydrogels for environmental remediation was investigated using Methylene Blue (MB), Rhodamine B (RD), and Bengal Rose (BR) as model contaminating dyes. An acrylate hydrogel network with incorporated CNT was synthesized by photo-polymerization without any preliminary derivatization of CNT surface. Thermodynamics, isothermal and kinetic studies showed favorable sorption processes with the application of an external 12 V electric field found to be able to influence the amount of adsorbed dyes: stronger interactions with cationic MB molecules (qexp and qexp12 of 19.72 and 33.45 mg g−1, respectively) and reduced affinity for anionic RD (qexp and qexp12 of 28.93 and 13.06 mg g−1, respectively) and neutral BR (qexp and qexp12 of 36.75 and 15.85 mg g−1, respectively) molecules were recorded. The influence of pH variation on dyes adsorption was finally highlighted by reusability studies, with the negligible variation of adsorption capacity after five repeated sorption cycles claiming for the suitability of the proposed systems as effective sorbent for wastewater treatment.

Removal of Non-Steroidal Anti-Inflammatory Drugs from Drinking Water Sources by GO-SWCNT Buckypapers

“…In order to follow the adsorption of NSAIDs as a function of time at different concentrations (1, 10, and 50 ppm) by neat SWCNT and 75% GO-SWCNT BPs, kinetic experiments were also performed (Figure 6). Experimental data were fitted by a non-linear optimization method [64] with a pseudo-first-order or a pseudo-second-order equation.…”

“…In order to follow the adsorption of NSAIDs as a function of time at differe trations (1, 10, and 50 ppm) by neat SWCNT and 75% GO-SWCNT BPs, kine ments were also performed (Figure 6). Experimental data were fitted by a non timization method [64] with a pseudo-first-order or a pseudo-second-order equ Table 1. Pseudo-first and pseudo-second-order adsorption rate constants, k 1 (min −1 ) and k 2 (g mg −1 min −1 ), and adsorption capacity per unit of adsorbent mass at equilibrium, q e (mg g −1 ), by SWCNT BPs and 75% GO-SWCNT BPs for the three different NSAIDs (50 ppm).…”

“…V is the volume of NSAID solution, and m is the mass of BPs. Experimental data were fitted by a non-linear optimization method [64] with the following Equations ( 7) and ( 8), respectively:…”