Publications by authors named "Chunyan Lang"

2 Publications

  • Page 1 of 1

Adsorption of Hg(II) in solution by mercaptofunctionalized palygorskite.

Environ Sci Pollut Res Int 2021 Jul 31. Epub 2021 Jul 31.

Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, No. 9 Wenyuan Road, Yadong New District, Nanjing, 210023, China.

In the past 10 years, the treatment and restoration of soil and water bodies contaminated by mercury and other heavy metals have received unprecedented attention and support from China's environmental protection authorities. The search for low-cost and high-efficiency adsorbents has become one of the research hotspots in this field. In this paper, a simple and environment-friendly method was used to graft 3-mercaptopropyl trimethoxysilane on the surface of palygorskite. The synthesized mercaptofunctionalized palygorskite (M-PAL) was characterized by XRD, FT-IR, BET and SEM-EDS, respectively, and its adsorption conditions, adsorption models and thermodynamic parameters for Hg were systematically investigated. The experimental results indicated that the saturated adsorption capacity of Hg on the M-PAL could reach 203.4 mg·g, within 120 min at pH 4 and 298 K. By analyzing the experimental data of adsorption kinetics and thermodynamics, it was found that the adsorption process of Hg conformed to the pseudo-second-order kinetic model, which belonged to chemical adsorption of the rate-controlled step; the Langmuir model better described the adsorption isotherm. The thermodynamic parameters obtained (ΔH=29.95 kJ·mol, ΔS=103.09 J·mol·K and ΔG<0) show that the whole process is a spontaneous endothermic process. When the concentration of Na, K, Ca, Mg, Cl, NO, HCO and CHO was 200 times that of Hg, although these organic acids had a slightly greater effect on the adsorption of Hg on mercaptofunctionalized palygorskite than inorganic ions, the adsorption capacity remained above 185 mg·g. The adsorption products could be still stable in simulated acid rain with pH 3, 4, 5, 6, 7 and oxalic acid solution with concentration of 1, 2, 3, 4 and 5 mmol·L, and the desorption rates were about 3%. Through XPS analysis, the specific coordination of Hg with the S atom on the surface of M-PAL was confirmed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11356-021-15637-0DOI Listing
July 2021

Simultaneous removal of nitrogen, phosphorus and COD in an integrated OCO reactor.

Environ Technol 2014 Sep-Oct;35(17-20):2628-33

An integrated OCO reactor with two side-ditch separators based on the anaerobic/anoxic/oxic (A2/O) process was developed for municipal wastewater treatment in this study. The effects of dissolved oxygen (DO) concentration, hydraulic retention time (HRT) and the ratio of chemical oxygen demand (COD) to total nitrogen (C/N) in the influent were investigated for optimization, in order to achieve the removal of total nitrogen (TN), total phosphorus (TP) and COD in the reactor simultaneously. When the DO concentration of 2.0 mg/L in the aerobic zone, HRT of 12 h and C/N ratio of 8:1 were applied in the reactor, the superior removal efficiencies of COD, TN and TP reached 96%, 81% and 92%, respectively. The modification in integrated OCO system was characterized by the mixing of the liquid refluxed from anoxic and aerobic zones with the influent in the anaerobic zone. And the risk of activated sludge bulking was decreased successfully by enhancing phosphorus removal without any chemical auxiliary methods. Quite precise prediction results with the correlation coefficients (R) of 0.9584-0.9948 were forecasted by the back-propagation neural network model. All the results indicated that the integrated OCO process is able to remove TN, TP and COD in a reactor simultaneously.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/09593330.2014.914574DOI Listing
September 2014
-->