Synthesis of Sodium Acrylate and Acrylamide Copolymer/GO Hydrogels and Their Effective Adsorption for Pb2+ and Cd2+
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- 作者：Shengfu He ; Fan Zhang ; Shenzhen Cheng ; Wei Wang
- 刊名：ACS Sustainable Chemistry & Engineering
- 出版年：2016
- 出版时间：July 5, 2016
- 年：2016
- 卷：4
- 期：7
- 页码：3948-3959
- 全文大小：649K
- 年卷期：0
- ISSN：2168-0485
文摘
A serial of cross-linked sodium acrylate and acrylamide copolymer/graphene oxide (P(AANa-co-AM)/GO) hydrogels with different mass ratios of acrylic acid (AA) to acrylamide (AM) and different contents of N,N-methylenebis(acrylamide) (MBA) were prepared via dispersive polymerization. The prepared hydrogels were characterized by XRD, FT-IR, TGA, SEM, and BET in detail. The removal efficiency of Pb2+ and Cd2+ on the P(AANa-co-AM)/GO hydrogel have been improved significantly due to the addition of 1.0 wt % of GO. The P(AANa-co-AM)/GO hydrogel with AA/AM = 1 and 0.8 wt % of MBA has the highest removal efficiency for Pb2+ and Cd2+ and a suitable swelling ratio, which was selected as the adsorbent for systematic adsorption of Pb2+ and Cd2+ from aqueous solutions. The adsorption capacity and removal efficiency of Pb2+ and Cd2+ on the P(AANa-co-AM)/GO hydrogel were dependent on pH, initial heavy metal ion concentration, and adsorbent dosage. The presence of 0.01–0.05 M Mg2+ or Ca2+ has an obvious effect on the adsorption of Cd2+. The adsorption kinetics and adsorption isotherms of Pb2+ and Cd2+ on the P(AANa-co-AM)/GO hydrogel followed a pseudo-first order model and the Langmuir isotherm model, respectively. The maximum adsorption capacity of Pb2+ and Cd2+ on the P(AANa-co-AM)/GO hydrogel were calculated to be 452.3 and 196.4 mg/g at 298 K, respectively. The XPS analysis revealed that the adsorption mechanism of Pb2+ and Cd2+ on the P(AANa-co-AM)/GO hydrogel was ascribed to the chelation of −COO– with Pb2+ and the ion-exchange of −COO–Na+ with Cd2+, respectively. The P(AANa-co-AM)/GO hydrogel possesses good reusability and excellent fixed-bed column operation performance, which suggests that the P(AANa-co-AM)/GO hydrogel can be considered as a promising adsorbent for removing heavy metal ions from practical wastewater.