Cai Yuling,Liang Bin,Fang Zhanqiang,Xie Yingying,Tsang Eric Pokeung
As a promising in situ remediation technology, nanoscale zero-valent iron (nZVI) can remove polybrominated diphenyl ethers such as decabromodiphenyl ether (BDE209) effectively, However its use is limited by its high production cost. Using steel pickling waste liquor as a raw material to prepare nanoscale zero-valent metal (nZVM) can overcome this deficiency. It has been shown that humic acid and metal ions have the greatest influence on remediation. The results showed that nZVM and nZVI both can effectively remove BDE209 with little difference in their removal efficiencies, and humic acid inhibited the removal efficiency, whereas metal ions promoted it. The promoting effects followed the order Ni 2+ >Cu 2+ >Co 2+ and the cumulative effect of the two factors was a combination of the promoting and inhibitory individual effects. The major difference between nZVM and nZVI lies in their crystal form, as nZVI was found to be amorphous while that of nZVM was crystal. However, it was found that both nZVM and nZVI removed BDE209 with similar removal efficiencies. The effects and cumulative effects of humic acid and metal ions on nZVM and nZVI were very similar in terms of the efficiency of the BDE209 removal.
To reduce costs and improve practicability, an ion imprinted magnetic chitosan (IMCS) was synthesized through co-precipitation using steel pickling waste liquor and chitosan and Cu(II) as template ions, which was then characterized by TEM, SEM, EDX, FTIR, XRD and VSM. The batch experiments were carried out for its potential application and high selectivity of Cu(II) removal, which were observed due to the paramagnetic properties and coordination reactions in the imprinted cavities. Kinetic studies revealed that the adsorption process followed a pseudo second-order model and the equilibrium data fit perfectly with the Langmuir isotherm model. The maximum adsorption capacity was 109.89 mg g−1. Negative values for ΔH0 and ΔG0 indicated an exothermic and spontaneous adsorption process. The adsorption process was found to be a chemical reaction and coordination complexes were formed between the metal ions and the groups of chitosan binding mainly in the “bridge model”. Moreover, 0.2 mol L−1 HCl solution was considered as the most appropriate eluent for regeneration. It showed a great performance in the experiments for practical copper wastewater and the process was considerably cost-effective.
危险品化学品经营许可证（带存储）