【摘要】：本文以廢棄核桃果皮為原料,氯化鋅為活化劑,制備出比表面積高、吸附效果好的活性炭,研究了核桃果皮活性炭及其改性產(chǎn)物對(duì)甲基橙和酸性品紅、對(duì)硝基苯酚、Pb2+和Cd2+的吸附性能,考察了吸附時(shí)間,p H,溶液初始濃度等因素對(duì)吸附性能的影響,并通過(guò)吸附等溫線和動(dòng)力學(xué)模型探討其吸附機(jī)理。實(shí)驗(yàn)采用正交設(shè)計(jì),以活化溫度、活化時(shí)間、活化劑濃度和粒徑大小為四因素,每因素三個(gè)水平,馬弗爐加熱法制備核桃果皮基活性炭,得到了氯化鋅活化法制備活性炭的最佳條件,通過(guò)極差分析和方差分析排列出最佳的制備工藝組合,即氯化鋅濃度50%,粒徑大小為60目,活化溫度600℃,活化時(shí)間1 h,在此條件下制備的活性炭比表面積達(dá)到1258.050 m2/g。制備的核桃果皮基活性炭對(duì)甲基橙和酸性品紅、對(duì)硝基苯酚、Pb2+和Cd2+吸附效果較好。氨水改性活性炭和氫氧化鈉改性活性炭對(duì)對(duì)硝基苯酚的最大飽和吸附量分別高達(dá)204.080和263.160 mg/g,雙氧水改性活性炭對(duì)Pb2+和Cd2+最大飽和吸附量為58.498和84.321 mg/g,說(shuō)明改性后活性炭的吸附效果更好。增加吸附時(shí)間,五種污染物的去除率和吸附量都增加,活性炭對(duì)甲基橙、酸性品紅和對(duì)硝基苯酚的吸附平衡時(shí)間皆為6 h,而對(duì)Pb2+和Cd2+的吸附平衡時(shí)間為5 h。增大五種污染物的初始濃度,結(jié)果表現(xiàn)為活性炭對(duì)其吸附量增大,去除率降低。溶液p H對(duì)吸附影響較大。核桃果皮基活性炭對(duì)甲基橙、酸性品紅和對(duì)硝基苯酚的最適宜吸附p H值分別為6、6和3,吸附量和去除率隨p H的減小而增大,對(duì)Pb2+和Cd2+的最適宜吸附p H值分別為4和4,吸附量和去除率隨p H的增大而增大。吸附等溫線擬合表明未改性的核桃果皮基活性炭對(duì)對(duì)硝基苯酚的吸附符合Langmuir模型,氫氧化鈉和氨水改性活性炭則符合Freundlich模型。經(jīng)堿性改性后活性炭對(duì)對(duì)硝基苯酚的吸附量、去除率都有增大,可得出堿性改性后的活性炭對(duì)對(duì)硝基苯酚的吸附效果更好。Freundlich模型能更好描述活性炭對(duì)Pb2+和Cd2+的吸附等溫線;Langmuir模型更能描述氧化活性炭對(duì)Pb2+的吸附等溫線。而Freundlich模型能更好地描述活性炭及氧化活性炭對(duì)Cd2+的吸附等溫線;甲基橙的吸附屬于單層吸附行為。五種污染物的吸附動(dòng)力學(xué)行為均符合準(zhǔn)二級(jí)動(dòng)力學(xué)方程。
[Abstract]:In this paper, activated carbon with high specific surface area and good adsorption effect was prepared by using waste walnut peel as raw material and zinc chloride as activator. The modified activated carbon from walnut peel and its modified products, such as methyl orange, acid fuchsin, p-nitrophenol, were studied. The adsorption properties of Pb2 and Cd2 were studied. The influence of the initial concentration of, p H, solution on the adsorption performance was investigated, and the adsorption mechanism was discussed by adsorption isotherm and kinetic model. Orthogonal design was used to prepare walnut pericarp based activated carbon with four factors, activation temperature, activation time, activator concentration and particle size, and three levels of each factor. The optimum conditions for the preparation of activated carbon by zinc chloride activation method were obtained. The optimum preparation conditions were obtained by means of range analysis and variance analysis. The optimum preparation conditions were as follows: zinc chloride concentration 50, particle size 60 mesh, activation temperature 600 鈩，

本文編號(hào)：2374828