桑树杆活性炭/铁锰氧化物复合吸附剂对磷的吸附研究
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摘要
采用原位合成法制备桑树杆活性炭/铁锰氧化物复合吸附剂(MSAC/Fe-Mn),用红外光谱、X射线衍射等对其表征,探讨MSAC/Fe-Mn对磷的吸附机理。研究pH值、吸附时间、初始浓度、温度和共存离子等因素对吸附效果的影响,结果表明,pH值为5时,其对磷的去除效果最好;共存离子对磷的吸附影响大小顺序为CO2-3> SO2-4> NO-3;随着离子强度由0. 05 mol/L(Na NO3)增大到0. 50 mol/L,复合吸附剂对磷的去除率降低了40. 6%;准二级动力学模型较好反映了吸附过程,Langmuir等温吸附模型适合拟合MSAC/Fe-Mn对磷的吸附,在温度为25,35,45℃时,其对磷的最大吸附量分别为16. 26,17. 78,20. 82 mg/g。MSAC/Fe-Mn吸附磷的机制包括静电、离子交换、物理-化学吸附等,MSAC/Fe-Mn中铁锰氧化物和其表面羟基和酚羟基均参与了吸附反应。
In this study,mulberry stem activated carbon/Fe-Mn oxide composite adsorbent(MSAC/Fe-Mn) is prepared by using in-situ synthesis method,in which the adsorption mechanism of phosphorus from aqueous solution onto MSAC/Fe-Mn is investigated and it is characterized by Fourier transform infrared spectroscopy(FTIR) and X-ray photoelectron spectroscopy(XPS). Batch experiments are performed to investigate effects of various experimental parameters such as pH,contact time,initial phosphorus concentration,temperature and the presence of competing anions on phosphorus adsorption on the MSAC/Fe-Mn. The results show that the optimal pH for phosphorus removal is 5,the sequence of the effects of coexisting anions on the adsorption follows: CO2-3> SO2-4> NO-3. The removal rate of phosphorus decreases by 40. 6% with the increase of ionic strength from 0. 05(Na NO3) to 0. 50 mol/L. The process of phosphorus adsorption follows pseudo-second-order kinetics,the adsorption data better fits Langmuir isotherm and the maximum adsorption capacity calculated from Langmuir isotherm model is 16. 26,17. 78 and 20. 82 mg/g at 25 ℃,35 ℃ and 45 ℃ respectively. The mechanism of phosphorus adsorption onto MSAC/Fe-Mn includes electrostatic,ion exchange and physical-chemical adsorption. Iron hydroxyl oxides and manganese oxide react with phosphate forming salts,and the surface hydroxyl groups and phenolic hydroxyl groups are involved in the adsorption.
In this study,mulberry stem activated carbon/Fe-Mn oxide composite adsorbent(MSAC/Fe-Mn) is prepared by using in-situ synthesis method,in which the adsorption mechanism of phosphorus from aqueous solution onto MSAC/Fe-Mn is investigated and it is characterized by Fourier transform infrared spectroscopy(FTIR) and X-ray photoelectron spectroscopy(XPS). Batch experiments are performed to investigate effects of various experimental parameters such as pH,contact time,initial phosphorus concentration,temperature and the presence of competing anions on phosphorus adsorption on the MSAC/Fe-Mn. The results show that the optimal pH for phosphorus removal is 5,the sequence of the effects of coexisting anions on the adsorption follows: CO2-3> SO2-4> NO-3. The removal rate of phosphorus decreases by 40. 6% with the increase of ionic strength from 0. 05(Na NO3) to 0. 50 mol/L. The process of phosphorus adsorption follows pseudo-second-order kinetics,the adsorption data better fits Langmuir isotherm and the maximum adsorption capacity calculated from Langmuir isotherm model is 16. 26,17. 78 and 20. 82 mg/g at 25 ℃,35 ℃ and 45 ℃ respectively. The mechanism of phosphorus adsorption onto MSAC/Fe-Mn includes electrostatic,ion exchange and physical-chemical adsorption. Iron hydroxyl oxides and manganese oxide react with phosphate forming salts,and the surface hydroxyl groups and phenolic hydroxyl groups are involved in the adsorption.
引文
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[14]蒋旭涛,迟杰.铁改性活性炭对磷的吸附及磷形态的变化特征[J].农业环境科学学报,2014,33(9):1817-1822.
[15]BISWAS K,GUPTA K,GOSWAMI A,et al,Fluoride removal efficiency from aqueous solution by synthetic iron(III)–aluminum(III)–chromium(III)ternary mixed oxide[J]. Desalination,2010,255:44–51.
[2]刘辉利,梁美娜,朱义年,等.氢氧化铁对砷的吸附与沉淀机理[J].环境科学学报,2009,29(5):1011-1020.
[3]童婧,杨朝晖,曾光明,等.锆、铁氧化物改性活性炭纤维的制备及其除磷性能[J].环境工程学报,2016,10(6):2881-2888.
[4]KANUNGO S B,TRIPATHY S S,MISHRA S K,et al.Adsorption of Co2+,Ni2+,Cu2+,and Zn2+onto amorphous hydrous manganese dioxide from simple(1–1)electrolyte solutions[J]. Journal of Colloid and Interface Science,2004,269:11-21.
[5]HAN R,ZOU W,LI H,et al. Copper(II)and lead(II)removal from aqueous solution in fixed-bed columns by manganese oxide coated zeolite[J]. Journal of Hazard Materials,2006,137(2):934–942.
[6]2016年广西壮族自治区国民经济和社会发展统计公报[EB/OL].(2017-05-11)[2017-11-01]. http://www. gxtj. gov. cn/tjsj/tjgb/qqgb/201704/t20170417_132996. html.
[7]常青,江国栋,胡梦璇,等.石墨烯基磁性复合材料吸附水中亚甲基蓝的研究[J].环境科学,2014,35(5):1804-1809.
[8]RAMESH C,SATOKO T,AKINARI S,et al. Selective adsorption of phosphate from seawater and wastewater by amorphous zirconium hydroxide.[J]. Journal of Colloid and Interface Science,2005,297(2). 426-433.
[9]LU J,LIU H,ZHAO X,et al. Phosphate removal from water using freshly formed Fe–Mn binary oxide:Adsorption behaviors and mechanisms[J]. Colloids and Surfaces A:Physicochemica L and Engineering Aspects,2014,455(1):11-18.
[10]LI G,GAO S,ZHANG G,et al. Enhanced adsorption of phosphate from aqueous solution by nanostructured iron(III)–copper(II)binary oxides[J]. Chemical Engineering Journal,2014,235:124-131.
[11]BISWAS B K,INOUE K,GHIMIRE K N,et al. Removal and recovery of phosphorus from water by means of adsorption onto orange waste gelloaded with zirconium[J]. Bioresource Technology,2008,99(18):8685-8690.
[12]HUANG W,CHEN J,HE F,et al. Effective phosphate adsorption by Zr/AL-pillared montmorillonite:insight into equilibrium,kinetics and thermodynamics[J]. Applied Clay Science,2015,104:252-260.
[13]LAI L,XIE Q,CHI L,et al. Adsorption of phosphate from water by easily separable Fe3O4&Si O2core/shell magnetic nanoparticles functionalized with hydrous lanthanum oxide[J]. Journal of Colloid and Interface Science,2016,465:76-82.
[14]蒋旭涛,迟杰.铁改性活性炭对磷的吸附及磷形态的变化特征[J].农业环境科学学报,2014,33(9):1817-1822.
[15]BISWAS K,GUPTA K,GOSWAMI A,et al,Fluoride removal efficiency from aqueous solution by synthetic iron(III)–aluminum(III)–chromium(III)ternary mixed oxide[J]. Desalination,2010,255:44–51.