膨胀石墨的制备及其对捕收剂吸附研究

发布时间：2018-12-12 17:29

【摘要】：膨胀石墨(EG)大多是由性状较好天然鳞片石墨利用化学或电化学等方法经氧化插层得可膨胀石墨(GIC),可膨胀石墨在高温焙烧下,由于石墨层间插入物产生的瞬间推动力,使得体积膨胀,增大几十到几百倍,得到的具有网络状孔隙的蠕虫状石墨膨胀体。膨胀石墨因其优良特性,广泛应用于众多行业,被称为21世纪最有发展潜力的新材料。选矿浮选废水中含有大量浮选药剂,处理工艺较复杂,经济效益不佳,直接排放,对环境危害较大,不符合绿色矿山要求。目前,膨胀石墨用于吸附油类研究较多,用于吸附其他药剂类污染物也日渐受到重视,而改性膨胀石墨用于选矿废水处理中吸附捕收剂的研究未见报道。本文经药剂筛选,以过氧化氢、硫酸、硝酸铵为氧化、插层剂制备膨胀石墨。通过控制单一变量的条件实验,得到制备最佳膨胀体积为255mL/g膨胀石墨的工艺流程,同时对制备出的膨胀石墨进行了扫描电镜表征,深入了解膨胀石墨的孔结构。将最佳工艺条件下所得膨胀石墨,进行三氯化铁改性实验,获得改性膨胀石墨(MEG)。在此基础上,主要研究了经改性所得膨胀石墨对浮选捕收剂苯甲羟肟酸(GYB)和黄药的吸附作用。吸附试验结果表明改性膨胀石墨对GYB的吸附平衡时间为5.5h,最大吸附量为16.31mg/g,GYB去除率最大为70.7%;对黄药的吸附平衡时间为60min,最大吸附量为18.87mg/g,黄药去除率最大为94.24%。分别用拟一级和拟二级反应模型来研究膨胀石墨对苯甲羟肟酸和黄药的吸附动力学,结果表明拟二级反应模型更适合用来表示膨胀石墨对药剂的吸附过程。此外,吸附热力学表明,膨胀石墨对苯甲羟肟酸的吸附符合Freundlich吸附模型,对黄药的吸附则符合Langmuir吸附模型。
[Abstract]:Expandable graphite (EG) is obtained by oxidation intercalation of natural flake graphite by chemical or electrochemical methods, and (GIC), expandable graphite is calcined at high temperature, which is caused by the instantaneous driving force produced by the intercalation between graphite layers. A worm-like graphite expander with network pores is obtained by increasing the volume by several dozen to several hundred times. Exfoliated graphite is widely used in many industries because of its excellent properties, and it is called the most promising new material in the 21 ~ (st) century. There are a large number of flotation reagents in flotation wastewater, the treatment process is complex, the economic benefit is not good, the direct discharge is not good, and it is harmful to the environment and does not meet the requirements of green mines. At present, expandable graphite is used to adsorb oil more and more, and adsorption of other pharmaceutical pollutants is paid more and more attention. However, the study of modified expanded graphite used for adsorbing collector in mineral processing wastewater has not been reported. In this paper, expanded graphite was prepared with hydrogen peroxide, sulfuric acid and ammonium nitrate as oxidizing agent. The optimum expansion volume of 255mL/g expanded graphite was obtained by controlling the condition of single variable. At the same time, the expanded graphite was characterized by scanning electron microscope, and the pore structure of expanded graphite was deeply understood. The modified expanded graphite (MEG).) was obtained by the experiment of ferric chloride modification under the best technological conditions. On this basis, the adsorption of the modified expanded graphite on the flotation collector benzohydroxamic acid (GYB) and xanthate was studied. The adsorption test results showed that the adsorption equilibrium time of modified expanded graphite to GYB was 5.5 h and the maximum adsorption capacity was 16.31 mg / g GYB. The adsorption equilibrium time of xanthate was 60 min, the maximum adsorption capacity was 18.87 mg / g, and the removal rate of xanthate was 94.24 mg / g. The adsorption kinetics of expanded graphite for benzohydroxamic acid and xanthate was studied by pseudo-first-order reaction model and pseudo-second-order reaction model, respectively. The results show that the pseudo-second-order reaction model is more suitable to describe the adsorption process of expanded graphite to the reagent. In addition, the adsorption thermodynamics showed that the adsorption of benzyl hydroxamic acid by expanded graphite was in accordance with the Freundlich adsorption model, and the adsorption of xanthate with Langmuir adsorption model.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ424.2;TD923.13

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