草酸-FeCl_3复合淋洗剂对Pb、Zn污染土壤淋洗效果研究
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摘要
采用草酸-FeCl_3复合淋洗剂对土壤中严重超标的Pb和Zn进行振荡淋洗试验,并研究了淋洗剂浓度、液土比、淋洗时间、淋洗次数等因素对重金属去除效率的影响,采用BCR形态分级法分析淋洗前后重金属形态的变化。结果表明,淋洗剂对土壤中Pb、Zn的去除效果从大到小依次为草酸-FeCl_3复合、FeCl_3、草酸。草酸-FeCl_3复合淋洗剂的最适淋洗条件为草酸浓度0.1 mol/L,FeCl_3浓度0.4 mol/L;淋洗时间8 h;液土比20 m L∶1 g;淋洗1次,Pb去除率达到85.71%,Zn去除率达到78.49%。草酸-FeCl_3复合淋洗剂对土壤中酸溶态、可还原态和可氧化态的Pb和Zn均具有较好的去除效果,有效去除了土壤中生物活性高的Pb和Zn,降低了其环境风险。
The paper is to devote itself to an evaluation of an effluent combined oxalic acid with FeCl_3 to remove Pb and Zn contaminants in the environmentally polluted soil in case the soil contaminated by high grade pollutants of Pb( 726. 0 mg/kg) and Zn( 756. 2 mg/kg). For the said study purpose,we have studied the best favorable washing conditions and the distribution of Pb and Zn contaminants when the washing activities are ready to go by using the oxalic acid-FeCl_3. The results of our study indicate that,as compared with the single washing agent to be used,the effluent mixed with oxalic acid and FeCl_3 has been found to be more effective for the aforementioned purpose. What is more,it has been proven to be more effective when FeCl_3 is used as a single washing agent than along with oxalic acid. The optimal dosage for oxalic acid and FeCl_3 account for 0. 1 mol/L and 0. 4 mol/L respectively. The other accompanying washing conditions can be illustrated as follows: the washing time to be taken: 8 h; the ratio of the liquid to solid: 20: 1( m L: g); and the washing cycles: 1 for a single factor control experiment. The Pb and Zn removing rates can be made to reach 85. 71% and 78. 49%,respectively.Through co-leaching,the mass ratio of Pb and Zn in the soil can be made to reach 103. 75 mg/kg and 163. 65 mg/kg,respectively,that is,to reach level two in accordance with the standard of the soil environment quality. And,finally,when analyzing the contaminants of Pb and Zn in the soil pre-and-pro the said coleaching activity done in BCR procedure,it can been found that the rate of Pb and Zn in the soil turns out to account for 3. 93% of the acid soluble,40. 49% for the reducible,5. 36% for the oxidizable,and 50. 22% for the residue of Pb. At the same time,the chief content constituent components in the soil are made of24. 68% of acid soluble,15. 65% of reducible,13. 79% of oxidizable,and,45. 88% of residue Zn. After leaching,the results show that the removal rates of Pb and Zn can be made to be so high as 100% of acid soluble,94. 77% of reducible,69. 57% of oxidizable,77. 53% of residue Pb and 100% of the acid soluble,93. 50% of reducible,79. 06% of oxidizable,only 57. 74% of residue Zn. What is more,the effluent proves to have a strong impact on the morphology of Pb because of the efficient removal of residue Pb,whereas the acid soluble,reducible and oxidizable Pb/Zn can be removed efficiently,too. In addition,they are very easy to be absorbed by the plants. Thus,it can be inferred that the soil washing by using the effluent combined with oxalic FeCl_3 can be used as an available form for successful removal of Pb and Zn,so as to reduce the human and environmental hazards of the remedial soil.
The paper is to devote itself to an evaluation of an effluent combined oxalic acid with FeCl_3 to remove Pb and Zn contaminants in the environmentally polluted soil in case the soil contaminated by high grade pollutants of Pb( 726. 0 mg/kg) and Zn( 756. 2 mg/kg). For the said study purpose,we have studied the best favorable washing conditions and the distribution of Pb and Zn contaminants when the washing activities are ready to go by using the oxalic acid-FeCl_3. The results of our study indicate that,as compared with the single washing agent to be used,the effluent mixed with oxalic acid and FeCl_3 has been found to be more effective for the aforementioned purpose. What is more,it has been proven to be more effective when FeCl_3 is used as a single washing agent than along with oxalic acid. The optimal dosage for oxalic acid and FeCl_3 account for 0. 1 mol/L and 0. 4 mol/L respectively. The other accompanying washing conditions can be illustrated as follows: the washing time to be taken: 8 h; the ratio of the liquid to solid: 20: 1( m L: g); and the washing cycles: 1 for a single factor control experiment. The Pb and Zn removing rates can be made to reach 85. 71% and 78. 49%,respectively.Through co-leaching,the mass ratio of Pb and Zn in the soil can be made to reach 103. 75 mg/kg and 163. 65 mg/kg,respectively,that is,to reach level two in accordance with the standard of the soil environment quality. And,finally,when analyzing the contaminants of Pb and Zn in the soil pre-and-pro the said coleaching activity done in BCR procedure,it can been found that the rate of Pb and Zn in the soil turns out to account for 3. 93% of the acid soluble,40. 49% for the reducible,5. 36% for the oxidizable,and 50. 22% for the residue of Pb. At the same time,the chief content constituent components in the soil are made of24. 68% of acid soluble,15. 65% of reducible,13. 79% of oxidizable,and,45. 88% of residue Zn. After leaching,the results show that the removal rates of Pb and Zn can be made to be so high as 100% of acid soluble,94. 77% of reducible,69. 57% of oxidizable,77. 53% of residue Pb and 100% of the acid soluble,93. 50% of reducible,79. 06% of oxidizable,only 57. 74% of residue Zn. What is more,the effluent proves to have a strong impact on the morphology of Pb because of the efficient removal of residue Pb,whereas the acid soluble,reducible and oxidizable Pb/Zn can be removed efficiently,too. In addition,they are very easy to be absorbed by the plants. Thus,it can be inferred that the soil washing by using the effluent combined with oxalic FeCl_3 can be used as an available form for successful removal of Pb and Zn,so as to reduce the human and environmental hazards of the remedial soil.
引文
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[12]SUN Tao(孙涛),LU Kouping(陆扣萍),WANG Hailong(王海龙).Advance in washing technology for remediation of heavy metal contaminated soils:effects of eluants and washing conditions[J].Journal of Zhejiang A&F University(浙江农林大学学报),2015,32(1):140-149.
[13]LIM M,KIM M J.Reuse of washing effluent containing oxalic acid by a combined precipitation-acidification process[J].Chemosphere,2013,90(4):1526-1532.
[14]MAKINO T,TAKANO H,KAMIYA T,et al.Restoration of cadmium-contaminated paddy soils by washing with ferric chloride:Cd extraction mechanism and bench-scale verification[J].Chemosphere,2008,70(6):1035-1043.
[15]CHEN Chunle(陈春乐),WANG Guo(王果),WANG Junwei(王珺玮).Leaching effect of three composite neutral salt solutions with hydrochlorid acid on removing Cd from a Cd-contaminated soil[J].Journal of Safety and Environment(安全与环境学报),2014,14(5):205-210.
[16]CHEN Dianbo(陈殿波),LU Jianwei(卢建伟).Low-temperature external-heat potassium dichromate oxidation-photo-colorimetric method for determination of organic carbon in dewatering sludge[J].Yunnan Chemical Technology(云南化工),2012,39(1):39-42.
[17]ZHANG Yanxiong(张彦雄),LI Dan(李丹),ZHANG Zuoyu(张佐玉),et al.A comparision study of two methods for mensuration of soil cation exchange capacity[J].Guizhou Forestry Science and Technology(贵州林业科技),2010,38(2):45-49.
[18]LIU Xuemei(刘雪梅),HUANG Yuanfang(黄元仿).An experiment study on employing laser grain-size analyzer to analyze soil mechanical composition[J].Chinese Journal of Soil Science(土壤通报),2005,36(4):579-582.
[19]ZHANG Linlin(张霖琳),LIANG Xiao(梁宵),JANARBEK Xiriphan(加那尔别克·西里甫汗),et al.Comparision of different pretreatment and analytical method of heavy metals in soil and sediment samples[J].Environmental Chemistry(环境化学),2013,32(2):302-306.
[20]PUEYO M,MATEU J,RIGOL A,et al.Use of the modified BCR three-step sequential extraction procedure for the study of trace element dynamics in contaminated soils[J].Environmental Pollution,2008,152(2):330-341.
[21]YANG Qixia(杨启霞),SUN Haiyan(孙海燕),QIN Shaoyan(秦绍艳),et al.Microwave digestion-FAAS determination of lead and cadmium in soil[J].Environmental Science and Technology(环境科学与技术),2005,28(5):47-49.
[22]LIU Peiya(刘培亚),LI Yujiao(李玉姣),HU Pengjie(胡鹏杰),et al.Column leaching of cadmium and lead from a contaminated soil using composite leaching agent[J].Soil Remediation(土壤修复),2015,33(1):163-167.
[23]YANG Bingfan(杨冰凡),HU Pengjie(胡鹏杰),LI Zhu(李柱),et al.Research on the wash condition using EDTA for a heavy metal severely contaminated agricultual soil[J].Soils(土壤),2013,45(5):928-932.
[2]TORRES L G,LOPEZ R B,BELTRAN M.Removal of As,Cd,Cu,Ni,Pb and Zn from a highly contaminated industrial soil using surfactant enhanced soil washing[J].Physics&Chemistry of the Earth,Parts A/B/C,2012,37/39:30-36.
[3]BOLAN N,KUNHIKRISHNAN A,THANGARAJAN R,et al.Remediation of heavy metal(loid)s contaminated soils—To mobilize or to immobilize?[J].Journal of Hazardous Materials,2014,266:141-166.
[4]GUO X,WEI Z,WU Q,et al.Effect of soil washing with only chelators or combining with ferric chloride on soil heavy metal removal and phytoavailability:field experiments[J].Chemosphere,2016,147:412-419.
[5]YANG Z,ZHANG S,LIAO Y,et al.Remediation of heavy metal contamination in calcareous soil by washing with reagents:a column washing[J].Procedia Environmental Sciences,2012,16(4):778-785.
[6]MAKINO T,SUGAHARA K,SAKURAI Y,et al.Restoration of cadmium contamination in paddy soils by washing with chemicals:Selection of washing chemicals[J].Environmental Pollution,2006,144(1):2-10.
[7]KULIKOWSKA D,GUSIATIN Z M,BULKOWSKA K,et al.Humic substances from sewage sludge compost as washing agent effectively remove Cu and Cd from soil[J].Chemosphere,2015,136:42-49.
[8]MENG Long(孟龙),ZHANG Shirong(张世熔),WANG Guiyin(王贵胤),et al.Removal efficiency of Zn from contaminated soil by water extract of four types of biological materials[J].Acta Scientiae Circumstantiae(环境科学学报),2015,35(4):1152-1156.
[9]ZOU Z L,QIU R L,ZHANG W H,et al.The study of operating variables in soil washing with EDTA[J].Environmental Pollution,2009,157(1):229-236.
[10]YI Y M,SUNG K.Influence of washing treatment on the qualities of heavy metal-contaminated soil[J].Ecological Engineering,2015,81(8):89-92.
[11]IM J,YANG K,JHO E H,et al.Effect of different soil washing solutions on bioavailability of residual arsenic in soils and soil properties[J].Chemosphere,2015,138:253-258.
[12]SUN Tao(孙涛),LU Kouping(陆扣萍),WANG Hailong(王海龙).Advance in washing technology for remediation of heavy metal contaminated soils:effects of eluants and washing conditions[J].Journal of Zhejiang A&F University(浙江农林大学学报),2015,32(1):140-149.
[13]LIM M,KIM M J.Reuse of washing effluent containing oxalic acid by a combined precipitation-acidification process[J].Chemosphere,2013,90(4):1526-1532.
[14]MAKINO T,TAKANO H,KAMIYA T,et al.Restoration of cadmium-contaminated paddy soils by washing with ferric chloride:Cd extraction mechanism and bench-scale verification[J].Chemosphere,2008,70(6):1035-1043.
[15]CHEN Chunle(陈春乐),WANG Guo(王果),WANG Junwei(王珺玮).Leaching effect of three composite neutral salt solutions with hydrochlorid acid on removing Cd from a Cd-contaminated soil[J].Journal of Safety and Environment(安全与环境学报),2014,14(5):205-210.
[16]CHEN Dianbo(陈殿波),LU Jianwei(卢建伟).Low-temperature external-heat potassium dichromate oxidation-photo-colorimetric method for determination of organic carbon in dewatering sludge[J].Yunnan Chemical Technology(云南化工),2012,39(1):39-42.
[17]ZHANG Yanxiong(张彦雄),LI Dan(李丹),ZHANG Zuoyu(张佐玉),et al.A comparision study of two methods for mensuration of soil cation exchange capacity[J].Guizhou Forestry Science and Technology(贵州林业科技),2010,38(2):45-49.
[18]LIU Xuemei(刘雪梅),HUANG Yuanfang(黄元仿).An experiment study on employing laser grain-size analyzer to analyze soil mechanical composition[J].Chinese Journal of Soil Science(土壤通报),2005,36(4):579-582.
[19]ZHANG Linlin(张霖琳),LIANG Xiao(梁宵),JANARBEK Xiriphan(加那尔别克·西里甫汗),et al.Comparision of different pretreatment and analytical method of heavy metals in soil and sediment samples[J].Environmental Chemistry(环境化学),2013,32(2):302-306.
[20]PUEYO M,MATEU J,RIGOL A,et al.Use of the modified BCR three-step sequential extraction procedure for the study of trace element dynamics in contaminated soils[J].Environmental Pollution,2008,152(2):330-341.
[21]YANG Qixia(杨启霞),SUN Haiyan(孙海燕),QIN Shaoyan(秦绍艳),et al.Microwave digestion-FAAS determination of lead and cadmium in soil[J].Environmental Science and Technology(环境科学与技术),2005,28(5):47-49.
[22]LIU Peiya(刘培亚),LI Yujiao(李玉姣),HU Pengjie(胡鹏杰),et al.Column leaching of cadmium and lead from a contaminated soil using composite leaching agent[J].Soil Remediation(土壤修复),2015,33(1):163-167.
[23]YANG Bingfan(杨冰凡),HU Pengjie(胡鹏杰),LI Zhu(李柱),et al.Research on the wash condition using EDTA for a heavy metal severely contaminated agricultual soil[J].Soils(土壤),2013,45(5):928-932.