Modification Of Activated Carbon And Its Adsorption Performance Of Copper In Wastewater

Wastewater containing copper is emitted from Copper smelting, processing, electroplating and other production processes. The copper concentrations in the wasterwater are as high as tens of milligrams per liter. The wastewater is the pollutants of the environment, which can affects not only the self-purification of water and, but also has detrimental effects on human health. The adsorption via activated carbon is widely used in the treatment of wastewater containing copper. Activated carbon has been characterized as a large surface area and good capacity of adsorption. However, it exhibits a poor performance for removal of copper irons from wastewater due to its high ash content and surface functional groups. Therefore, it has important significance to improve the adsorption capability of activated carbon to copper irons by modification.The activated carbons modified by EDTA-Na2 and O3 were prepared and applied to the removal of the copper irons in the wastewater. The results indicated that the removal rate of Cu2+ in wastewater was up to 90.8% when the adsorbent was modified with 50 mg/L EDTA-Na2 for 40 min and the solid-liquid ratio of 1:10 at 124 ℃,0.14 MPa. Compared to un-modified carbon, the removal rate of Cu2+ was increased by 29.9%. The removal efficiency was decreased 5.1% in the progress of treating the mixing wastewater containing Cu2+、Zn2+ and Ni2+.And the activated carbon was oxidated by O3 at 25℃ for 2.5 h, its removal rate of Cu2+ reaches 73.5%. Compared to un-modified carbon, the removal efficiency was increased by 12.6%. It reaches 72.1% of Cu2+ removal when treating the mixing wastewater containing Cu2+、Zn2+、 Ni2+.BET, SEM, FT-IR and XRD were employed to investigate the influence of modifications to surface structure and adsorption performance of active carbons. Compared with the pure active carbons, the surface of modified samples become smoother, many small particles disappeared, and the specific surface area and pore volume decreases.The amount of hydroxyl was increased, indicating the increase of the active site, which led to the improvement of the Cu2+ removal.The subject explores theory and kinetics of Cu2+ adsorption capabilitydemonstrate that two kinds modified carbon adsorption isotherm of Cu2+ has a higher consistency with Langmuir than Freundlich, so they belong monolayer adsorption. Furthermore, the analysis of modified activated carbon adsorption kinetics of Cu2+ indicating that adsorption reaction of two kinds of activated carbons is more likely to satisfy Lagergren kinetics rate equation Ⅱ, the fitting correlation coefficient is 0.9985 and 0.9766, respectively.