(1. 中南大學 冶金與環(huán)境學院，長沙 410083；
2. 湖南城市學院 市政與測繪工程學院，益陽 413000)
摘 要: 采用雙滴共沉淀法制備MgO-LDH水滑石去除溶液中氟，并采用靜態(tài)實驗系統(tǒng)地討論溶液初始pH值、氟初始濃度和吸附時間等因素對MgO-LDH吸附性能影響。結(jié)果表明：吸附條件對氟的吸附能力影響較大，適宜的MgO-LDH投加量為10 g/L，溶液初始pH為6.40；隨著溫度的升高，MgO-LDH的吸附量也隨之增加。在較佳的實驗條件下，MgO-LDH對氟的最大吸附量為16.60 mg/g。動力學數(shù)據(jù)分析顯示，準二級動力學方程(R2=0.9314~ 0.9907)比準一級動力學方程(R2=0.7941~0.9919)能更好地描述吸附動力學特征。顆粒內(nèi)擴散方程擬合結(jié)果發(fā)現(xiàn)，氟在MgO-LDH吸附過程包括表面吸附和顆粒內(nèi)擴散兩個過程。吸附等溫數(shù)據(jù)擬合發(fā)現(xiàn)，Langmuir吸附等溫式(R2=0.9982~0.9992)比Freundlich吸附等溫式(R2=0.6904~0.9453)更好地描述氟在MgO-LDH上的等溫吸附行為。
關(guān)鍵字: MgO-LDH；含氟廢水；吸附等溫線；吸附動力學
（1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. School of Municipal and Mapping Engineering, Hunan City University, Yiyang 413000, China）
Abstract:The magnesium oxide layer double hydrotalcite (MgO-LDH) was prepared by double drop co-precipitation using magnesium oxide as magnesium source. And it was applied for the treatment of wastewater containing fluoride. The influences of initial fluoride concentration, pH and adsorption time on fluoride adsorption using MgO-LDH were investigated by the batch experiments. The experimental results show that the adsorption capacity for fluoride is affected by the adsorption conditions. The suitable adsorbent dosage is 10 g/L, the suitable pH of MgO-LDH fluorine adsorption is 6.40. The amount of adsorption increase with increasing the temperature. The adsorption capacity of the adsorbent for Fluoride is 16.60 mg/g at optimal conditions. The kinetic data show that the pseudo-second-order model (R2=0.9314-0.9907) can better describe the characteristic of the adsorption kinetic than the pseudo-first-order model (R2=0.7941-0.9919). The results from the Intra-particle model also show that there exist two separate stages in sorption process, which are external diffusion and the diffusion of inter-particle. Langmuir and Freundlich isotherms were used to fit the adsorption equilibrium data, and it is found that the adsorption process follows preferably the Langmuir isotherm adsorption model, which indicates that the adsorption mainly occurs in active region on the surface of MgO-LDH and belong to the monolayer adsorption.
Key words: MgO-LDH; wastewater containing fluoride; adsorption isotherm; adsorption kinetic
