摘要
本研究通过一步合成法,以二氨基胍盐酸盐(DH)为改性剂,以戊二醛为交联剂,制备了氨基功能化氧化石墨烯(DH-GO)。利用单一变量法优化制备条件后,得到最优参数为:改性时间2.5 h,温度35℃,pH=10,m(GO∶DH)=1∶5。通过红外和拉曼光谱、扫描电镜等手段对DH-GO进行了形貌的表征和结构的分析,发现改性材料表面因氨基的引入,导致ID/IG比值变大,表面负载了许多不规则晶状颗粒。批量吸附实验结果表明:pH对材料的性能影响大,这与材料表面的带电情况、Cr(Ⅵ)的主要存在形态相关;当pH为2时,对Cr(Ⅵ)的吸附容量达到最大。吸附在480 min内可达到平衡,符合拟二级动力学、Langmuir等温模型,主要为单层吸热的化学反应,据此可推测25℃时理论最大吸附容量为133.16 mg·g^(-1)。高浓度的NO_(3)-和Cl^(-)并不干扰吸附的进行,但高浓度的SO_(4)^(2-)和PO_(4)^(3-)对吸附会有一定的抑制作用。4次循环再生后DH-GO的吸附容量下降了约10%,仍保持着良好的再生性能。吸附机理主要是氨基官能团与水中的H^(+)结合并质子化后,与带负电的Cr(Ⅵ)产生静电吸引和反应,同时,羧基和羟基的结合作用、比表面能带来的物理吸附也是另一贡献者。以上研究结果可为GO改性材料应用于含Cr(Ⅵ)废水处理提供参考。
The amino-functionalized GO(DH-GO)was prepared by one-step method using diaminoguanidine hydrochloride(DH)as the modifier and glutaraldehyde as the crosslinking agent in this study.After being optimized with the single variable method,the preparation parameters were selected as follows:the modification time of 2.5 h,35℃,pH 10,m(GO∶DH)=1∶5.The morphology and structure was characterized by Infrared and Raman spectroscopy,Scanning electron microscopy,which indicated that amino groups introduction caused the increase of ID/IG value,and many irregular crystalline particles were loaded on the surface.The batch experiments showed that pH had a significant influence on the adsorption capacity of material,which was related to the surface charge of DH-GO and the main existing forms of Cr(Ⅵ).At pH 2,the Cr(Ⅵ)adsorption capacity of DH-GO reached its peak value.The adsorption reached the equilibrium within 480 min,the process was well fitted with the pseudo-second-order dynamics model and Langmuir isotherm model,indicating the monolayer endothermic chemical reaction occurred,and the maximum adsorption capacity at 25℃was theoretically estimated to be 133.16mg·g^(-1).NO_(3)-and Cl-at high concentrations had slight interference with the adsorption process,while SO_(4)^(2-)and PO_(4)^(3-)at high contents had the inhibitory effect to some extent.The adsorption capacity of DH-GO after four cycles of regeneration decreased by about 10%,and maintained a good regeneration performance.The adsorption mechanism was mainly proposed that amino functional groups was firstly protonated by the H+in the solution at pH 2,and then electrostatically attracted and reacted with negatively charged Cr(Ⅵ).The bonding of Cr(Ⅵ)to carboxyl and hydroxyl groups,and physical adsorption resulting from the high surface area also contributed to adsorption.This is an attempt to modify GO with amino groups,the findings could provide a reference for the application of the modified GO-based materials in Cr(Ⅵ)wastewater treatment.
作者
李明恩
冯庆革
林海英
胡秋艳
银昱婧
黄丽欣
王道铭
何玉花
李明治
LI Mingen;FENG Qingge;LIN Haiying;HU Qiuyan;YIN Yujing;HUANG Lixin;WANG Daoming;HE Yuhua;LI Mingzhi(School of Resources,Environment and Materials,Guangxi University,Nanning 530004,China;Guangxi Universities Key Laboratory of Environmental Protection,Guangxi University,Nanning 530004,China)
出处
《环境工程学报》
CAS
CSCD
北大核心
2022年第3期926-936,共11页
Chinese Journal of Environmental Engineering
基金
广西自然科学基金面上项目(2020GXNSFAA297011,2018GXNSFBA050008)
国家自然科学基金地区项目(22166006)。
