β-萘酚改性活性炭及其对钴吸附性能的研究

Study on activated carbon modified by beta naphthol and its adsorption properties of cobalt

采用β-萘酚改性制备选择性吸附钴的活性炭材料,SEM和FTIR表征测试发现,活性炭改性中受到溶胀作用,颗粒变粗大和疏松,表面结构中官能团和基团增多。并研究了β-萘酚浓度、改性时间、改性温度等改性条件对钴吸附性能的影响。同时探讨了改性活性炭吸附时间、温度、剂量等条件对吸附效率的影响,通过对等温吸附模型进行拟合,研究改性活性炭吸附钴的行为。结果表明,β-萘酚改性活性炭对钴吸附的优化工艺为氢氧化钠溶解β-萘酚后与亚硝酸钠按1∶1摩尔比混合配制α-亚硝基-β-萘酚溶液,浓度为1 mol/L、改性时间1.5h、温度95~100℃、吸附时间1h、吸附温度25℃、溶液中性条件下,钴吸附率达到99%以上,钴吸附平衡浓度下降到1mg/L以下,最大吸附容量为25.52mg/g。吸附等温线符合Langmuir等温线模型,拟合系数为0.99995,表明改性活性炭对钴的吸附模式是以单层吸附为主。

The activated carbon materials with selective adsorption of cobalt were prepared by using beta naphthol.The characterization results of SEM and FTIR show that because of the swelling effect in activated carbon modification,the particles become coarse and loose,and the functional groups and groups in surface structure are increased.The effects of modification conditions of concentration of beta naphthol,time,and temperature on adsorption property of cobalt were studied.The effects of adsorption time,adsorption temperature and the dosage of activated carbon on the adsorption ratio were investigated.Through fitting the isothermal adsorption model,the adsorption behavior of cobalt of modified activated carbon was studied.The optimizing process of activated carbon modified by beta naphthol and adsorption of cobalt is obtained.The 1-nitroso-2-naphthol solution was mixed by beta naphthol dissolved in sodium hydroxide solution and sodium nitrite with molar ratio of 1∶1.When the concentration of 1-nitroso-2-naphthol solution is 1 mol/L,reaction time is 1.5 h,reaction temperature is 95-100 ℃,and adsorption time is 1 h,the adsorption rate of modified activated carbon reaches 99.7%in neutral solution,the cobalt adsorption equilibrium concentration decreases blow 1 mg/L,and the maximum adsorption quantity is 26.18 mg/g.The adsorption isothermal is in accordance with Langmuir isothermal model and the linear fitting coefficient is 0.99999,which indicating that the adsorption model of modified activated carbon to cobalt mainly depends on monolayer adsorption.