Rong He,Zhihong Wang,Lei Tan,Yi Zhong,Weiming Li,Da Xing,Chaohai Wei,Youwen Tang
We developed two types of novel highly ordered Ni 2+ imprinted mesoporous organosilica materials (SBA-15 (NiIMS1) and MCM-41 (NiIMS2)) through co-condensation for selective adsorption of Ni 2+ from electroplating Ni 2+ effluents. FTIR and solid-state 13 C NMR spectra demonstrated the successful embedment of functionalized iminodiacetic acid and ethanediamine chelating groups in NiIMS1 and NiIMS2, respectively. X-ray photoelectron spectroscopy analysis confirmed that Ni 2+ was coordinated by N atom and carboxyl O atom of the functional groups. Furthermore, NiIMS1 and NiIMS2 displayed highly ordered periodic hexagonal P6mm meso-structure, large surface area, and highly specific recognition ability toward Ni 2+ . The adsorption experimental results proved that NiIMS1 was suitable for acidic wastewater treatment , whereas NiIMS2 was fit for alkaline wastewater. The saturated adsorption capacity of NiIMS2 was 20.8 mg/g at pH 6.0, and that of NiIMS1 reached up to 22.9 mg/g at pH 3.0. The values of selectivity coefficients of NiIMS1 and NiIMS2 for five competing metal ions ranged from 46.4 to 12.4 and 36.9 to 18.8, respectively. The adsorption efficiency of NiIMS1 was above 92.5% even after seven extraction-stripping cycles, while that for NiIMS2 was 90.9%. The real sample adsorption experiments demonstrated that these mesoporous organosilica materials have high potential for water treatment applications.
Heterogeneous process with low mass transfer rate is limited in the treatment of large-volume Ni-containing wastewater. The homogeneous reaction provides a promising strategy to solve this problem, but phase transition process of Ni 2+ removal and its potential impact on activated sludge system are rarely explored. Herein, the Ni 2+ removal efficiency and process were firstly investigated in detail by using S-containing reagent with dithioamino groups. When the dosage of reagent concentration was controlled at 5–10:1(Ni), Ni 2+ can be rapidly and completely removed within 1 min. Additionally, other coexisting Cu 2+ , Co 2+ , Cd 2+ , and Pb 2+ could be synchronously removed with more reagent adding, while the typical organics (e.g., humic/citric acid) in water and high concentration of chemical oxygen demand (3800 mg L −1 ) in actual wastewater, exhibited negligible inhibition for Ni 2+ capture. The phase transition was visually investigated by charge coupled device camera and paticle size change. Experimental characterizations demonstrate that the dithioamino groups in capture reagent could efficiently chelate with Ni 2+ , which can be validated by the theoretical calculations. Vitally, the utilization of reagent cannot affect the nitrification activity of aerobic sludge system through short-term experiment and 29 months of operation while ensuring total Ni removal efficiency. These findings highlight an opportunity for using S-containing organic reagents to remove heavy metal ions from actual wastewater, especially in the application of the sewage treatment plant with bulky water.
A novel efficient Ni 2+ adsorbent A-type zeolite is successfully synthesized. It is worth noting that the raw material used is the waste coal ash produced by local power plants. The ability of A-type zeolite to remove Ni 2+ from wastewater is up to 94%. In the study, the physical properties of zeolite are systematically characterized. In addition, we study in detail the effect of the external environment on the adsorption capacity of A-type zeolite. Moreover, the pseudo secondary kinetic model and Langmuir isothermal model evaluate the kinetic performance and isothermal equilibrium adsorption ability are better. The synthetic zeolite not only effectively uses the coal fly ash, but also realizes the sewage recycling. Therefore, the use of power plant coal fly ash to make adsorbent zeolite has potential practical significance.
危险品化学品经营许可证（带存储）