凹凸棒石_炭对低浓度亚甲基蓝的吸附性能.pdf
《凹凸棒石_炭对低浓度亚甲基蓝的吸附性能.pdf》由会员分享,可在线阅读,更多相关《凹凸棒石_炭对低浓度亚甲基蓝的吸附性能.pdf(8页珍藏版)》请在文库网上搜索。
1、文章编号:摇 1007鄄8827(2015)01鄄0071鄄08凹凸棒石/ 炭对低浓度亚甲基蓝的吸附性能吴雪平1,摇 徐艳青1,摇 张先龙1,摇 吴玉程2,摇 高摇 鹏1(1. 合肥工业大学 化学与化工学院, 安徽 合肥 230009;2. 合肥工业大学 材料科学与工程学院,安徽 合肥 230009)摘摇 要:摇 通过水热处理凹凸棒石和纤维素获得凹凸棒石/ 炭纳米复合材料,研究该复合材料对亚甲基蓝的吸附性能。 考察吸附条件对吸附行为的影响,以及吸附动力学和热力学研究。 亚甲基蓝的吸附行为符合二级吸附速率方程,吸附等温方程符合 Langmuir 方程。 吸附热力学参数的计算值表明,亚甲基蓝在该复
2、合材料上的吸附是自发、吸热的过程。关键词:摇 凹凸棒石/ 炭; 亚甲基蓝; 吸附;动力学;热力学 中图分类号: 摇 TQ127. 1+1文献标识码: 摇 A收稿日期:2014鄄05鄄27;摇 修回日期:2014鄄12鄄09基金项目:国家自然科学基金(51002042, 40902020, 51072044);安徽省教育厅重点项目 (2011AJZR0080);中央高校基本科研业务费专项资金资助(2013HGQC0015).通讯作者:吴玉程,教授. E鄄mail: ycwu hfut. edu. cn作者简介:吴雪平,副教授. E鄄mail: xuepingw ustc. edu. cnAdso
3、rption of low鄄concentrationmethylene blue onto a palygorskite/ carbon compositeWU Xue鄄ping1,摇 XU Yan鄄qing1,摇 ZHANG Xian鄄long1,摇 WU Yu鄄cheng2,摇 GAO Peng1(1. School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei230009, China;2. School of Materials Science and Engineering,
4、 Hefei University of Technology, Hefei230009, China)Abstract: 摇 A palygorskite/ carbon composite was prepared through hydrothermal treatment of palygorskite and cellulose, and itsadsorption behavior for methylene blue (MB) was investigated. The effect of adsorption conditions on the capacity and kin
5、etics wasalso investigated. The adsorption kinetics of MB onto the composite is best described by a pseudo鄄second鄄order equation. The ad鄄sorption isotherms conform to the Langmuir isothermal adsorption equation. The adsorption thermodynamic parameters calculatedfrom the isotherms indicate that the a
6、dsorption of MB on the composite is endothermic.Keywords:摇 Palygorskite/ carbon; Methylene blue; Adsorption; Kinetics; IsothermReceived date: 2014鄄05鄄27;摇 Revised date: 2014鄄12鄄09Foundation item: National Natural Science Foundation of China (51002042, 40902020, 51072044); Programs Foundation of Pro鄄
7、vincial Education Department of Anhui ( 2011AJZR0080 ); Fundamental Research Funds for the CentralUniversities (2013HGQC0015).Corresponding author: WU Yu鄄cheng, Professor. E鄄mail: ycwu hfut. edu. cnAuthor introduction: WU Xue鄄ping, Associate Professor. E鄄mail: xuepingw ustc. edu. cnEnglish edition a
8、vailable online ScienceDirect ( http:蛐蛐www. sciencedirect. com蛐science蛐journal蛐18725805 ).DOI: 10. 1016/ S1872鄄5805(15)60176鄄71摇 IntroductionMethylene blue (MB) is a common contaminantin wastewater from dye industries. MB is toxic anddifficult to remove completely because of its stable aro鄄matic str
9、ucture that contains chromophores and polargroups1. Many technologies were developed for thetreatment of dye wastewater, such as microbial degra鄄dation, oxidation, adsorption and coagulation. Amongthese technologies, adsorption has attracted considera鄄ble attentions because of its simplicity and low
10、 lost,which is especially effective for the removal of low鄄concentration contaminants1鄄8. Many types of adsor鄄bents have been used for the adsorption of MB. Someof these adsorbents include active carbon4,5, biomassresources6,7, clays2,3, clay composites8, nanoma鄄terials1, et al. In the last decades,
11、 clay minerals havedemonstrated an excellent adsorption ability for the re鄄moval of contaminants because of their large quanti鄄ties, chemical and mechanical stability, high surface摇第 30 卷摇 第 1 期2015 年 2 月新摇 型摇 炭摇 材摇 料NEW CARBON MATERIALSVol. 30摇 No. 1Feb. 2015摇area and porous properties.Palygorskite
12、 ( Mg5-y-zRy3+驻z)(Si8-xRx3+)O20(OH2)4E2+(x-y+2z) /2(H2O)4,which is abundant in Jiangsu and Anhui provinces, is ahydrated magnesium aluminum silicate presented in na鄄ture as a nano鄄fibrous clay mineral. Palygorskite, alsoknown as attapulgite, is an excellent adsorbent materialbecause of its large sur
13、face area and ion鄄exchanging a鄄bility2,8鄄10. The zeolite鄄like channel is easily filled bypolar micro鄄molecules, suchaswatermolecules,which renders the palygorskite organophilic to organiccontaminants. Organic modification of palygorskite u鄄singsurfactantmaterials,suchasN鄄methylimid鄄azole11, is a com
14、mon method for improving its re鄄moval efficiency for organic contaminants. However,surfactant modification has some limitations, includinghigh cost and complexity.In our previous work, the organic modificationof palygorskite was successfully achieved through anovellow鄄cost,facileandgreenhydrothermal
15、process12. The organophilic property of palygorskiteis highly enhanced because of the loading of nanocar鄄bons with organic groups (CH2and CH3), as con鄄firmed by the adsorption of phenol from aqueous solu鄄tion. Many saccharides are good carbon sources forpreparingcarbonmaterialsbyhydrothermalprocess1
16、2, 13. Cellulose is the cheapest and most a鄄bundant among all natural biomass. Carbon materialswith different structures can be obtained by hydrother鄄mal treatment or calcination of cellulose13.In this paper, we prepared palygorskite/ carbonnanocomposite using cellulose as carbon source by hy鄄drothe
17、rmal method.In the hydrothermal process,soluable ammonium iron ( II) sulfate hexahydrateFeSO4(NH4)2SO46H2O was added to catalyzethe carbonization. The adsorption of low鄄concentra鄄tion MB onto palygorskite/ carbon nanocomposite wasinvestigated. The concentration of MB was lower than100 mg/ L. The eff
18、ect of adsorption conditions on theremoval rate of MB was investigated. The adsorptionmechanism was discussed through adsorption kineticsand isotherms.2摇 Experimental2. 1摇 Raw materialsPalygorskitewasobtainedfromGuangshan,Mingguang City, China.The palygorskite contentwas 98%, and the clay contained
19、a small amount ofdetrital quartz. The chemical composition of the claywas 34. 50% SiO2, 22. 36% Al2O3, 13. 14% MgO,3. 30% Fe2O3, 0. 12% FeO and 26. 58% other impu鄄rities. The reagents included analytical reagent鄄gradeglucose and ammonium iron (II) sulfate hexahydrateFeSO4(NH4)2SO46H2O, which were pu
20、rchasedfrom Shanghai Chemical Reagent Factory.2. 2 摇Preparation of palygorskite/ carbon nano鄄compositePalygorskite/ carbon nanocomposite was preparedaccording to a previously method12,14.Cellulose(5 g) and FeSO4(NH4)2SO46H2O (2. 97 g) weredissolved in 72 mL of distilled water in a 100 mLbeaker. The
21、beaker was placed on a magnetic stirrer,and the solution was constantly stirred to completelydissolve the powders. Then, palygorskite (2. 5 g)was added and the solution was stirred for 2 h at roomtemperature. The final suspension was transferred to aTeflon鄄lined stainless steel autoclave (100 mL of
22、totalinner volume), sealed and maintained at 220 益 for48 h. After the reaction, the black product was cen鄄trifuged, washed with double鄄distilled water and etha鄄nol for several times, and then dried at 60益.2. 3摇 CharacterizationPowder X鄄ray diffraction (XRD) patterns wereobtained using a Rigaku D/ ma
23、x鄄rB X鄄ray diffractom鄄eter with Cu K琢 radiation operated at 40kV,100 mA, and 4毅min-1.Nitrogen adsorption wasused to obtain porous properties of the sample using aTriStar II 3020 V1. 03 and surface area was analyzedusing Brunauer鄄Emmett鄄Teller (BET) method.2. 4摇 Adsorption studiesPalygorskite/ carbon
24、 adsorbent and MB solutionwere mixed in a 25 mL conical flask with stirring.The solution pH was adjusted using 0. 1 mol/ L HClor 0. 1 mol/ L NaOH solution. The pH of the solutionwas determined using a China PHS鄄25 detector. Theremoval rate of MB was calculated using Eq. (1),where 籽0and 籽eare the ini
25、tial and equilibrium concen鄄trations of MB, respectively.D% =(籽0-籽e) / 籽0100%(1)The concentration of MB was analyzed with aspectrophotometry (722, Shanghai Phoenix OpticalInstrument Co. , China) at a wavelength of 665 nm.3摇 Results and discussion3. 1摇 Characterization of the adsorbentsThe scanning e
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 凹凸 浓度 甲基 吸附 性能