固定香菇废弃菌柄对铅和镉的生物吸附研究
文献类型：学位论文
| 作者 | 马培 |
| 学位类别 | 硕士 |
| 答辩日期 | 2009 |
| 授予单位 | 中国科学院水利部成都山地灾害与环境研究所 |
| 授予地点 | 成都 |
| 导师 | 张丹 |
| 关键词 | 香菇废弃菌柄 固定 生物吸附 共存离子 机理 |
| 其他题名 | Biosorption of Cd(Ⅱ) and Pb(Ⅱ) from Water Solution by Immobilized Lentinus edodes Residue |
| 学位专业 | 自然地理学 |
| 中文摘要 | 随着全球经济的快速发展，废水的大量排放，导致近年来，许多重金属对环境的污染日益严重。如何有效地治理重金属污染已经成为人类共同关注的问题。其中生物吸附技术是处理重金属污染水体的一项有效技术，最近几年在此基础上发展的固定技术更是把废水处理提高到新的水平。本文用固定技术固定香菇废弃菌柄，研究吸附去除废水中普遍存在毒性较大的铅和镉，得出以下结果。 1 聚乙烯醇-海藻酸钠是提高香菇吸附能力的最佳固定材料 用海藻酸钠(SA)、聚乙烯醇(PVA)和琼脂作为香菇(Lentinus edodes)废弃菌柄的固定材料。比较了三种材料的成球性、耐酸性、机械强度和铅、镉吸附能力的特性，选出了PVA为固定材料。以PVA、SA、氯化钙和菌粉浓度为因素，设计正交实验。结果显示，影响PVA-SA固定香菇吸附铅的因素主次关系为氯化钙浓度>菌粉浓度>PVA浓度>SA浓度：影响PVA-SA固定香菇吸附镉的因素主次关系为PVA浓度>氯化钙浓度>SA浓度>菌粉浓度；由方差分析可知，PVA、SA、氯化钙和菌粉浓度对PVA-SA固定香菇铅的吸附率的影响均不显著，PVA浓度(P<0.05)对PVA-SA固定香菇镉的吸附率有显著影响，其它三个因素影响均不显著。吸附铅的PVA-SA固定香菇的最佳配方是8%PVA+1%SA+3%菌粉+2%氯化钙的饱和硼酸，对铅吸附率为95.4%：吸附铅的PVA-SA固定香菇的最佳配方是5%PVA+1%SA+3%菌粉+2%氯化钙的饱和硼酸，对镉吸附率为63.7%，二小球成球性、机械强度和耐酸性都较好。 2 获得了吸附铅和镉的理想影响因子条件 (1)震荡吸附时间的影响 自由香菇吸附铅和镉的平衡时间为60 min，平衡吸附量(qe)分别为1.812 mg/g和0.844mg/g；PVA-SA固定香菇吸附铅和镉的吸附平衡时间分别为3h和7h，平衡吸附量分别为0.2008和0.4925 mg/g。 (2)溶液pH值的影响 随着pH值增加，PVA-SA固定香菇和自由香菇对铅和镉的吸附率逐渐增加。pH4～7为自由香菇吸附铅的适宜范围，pH6～7为PVA-SA固定香菇吸附铅的适宜范围；PVA-SA固定香菇吸附镉的适宜pH范围是4～7，自由香菇吸附镉适宜pH值吸附范围是6～7。 (3)初始金属离子浓度的影响 随着铅和镉初始浓度增加(0 mg/L～120 mg/L)，PVA-SA固定香菇对铅和镉的吸附量有线性增加的趋势，当金属离子浓度为120 mg/L时，铅和镉的吸附量分别为14.874 mg/g和5.462 mg/g。随着铅和镉的浓度增加(0 mg/L～100 mg/L)，自由香菇的金属吸附量先增加，当铅和镉浓度60 mg/L时，自由香菇铅和镉的吸附量趋于饱和，饱和吸附量为8.535 mgPb/g和2.819 Cdmg/g。 (4)吸附剂浓度的影响 随着吸附剂浓度的增加，固定和自由香菇重金属吸附率缓慢增加但吸附量降低。 (5)竞争性吸附 当共存离子铜/镉的浓度较低时(≤10 mg/L)促进了自由香菇对铅的吸附，降低了固定香菇对铅的吸附率；当共存离子的浓度从10 mg/L增至30 mg/L，铜使自由香菇对铅的吸附率从80.02%降至16.21%，镉使自由香菇对铅的吸附率从81.02%降至70.65%；铜使固定香菇对铅的吸附率从65.84%增至84.86%，镉使固定香菇对铅的吸附率从83.32%增至84.15%。共存离子(铜/铅)降低了自由香菇和固定香菇对镉的吸附率，且共存离子对自由香菇吸附镉的负干扰作用更强烈。方差分析结果表明在p=0.01的水平上，干扰离子对两种吸附剂吸附铅、镉有明显的干扰作用。 3 初步探明了固定香菇吸附铅和镉的机理 (1)热力学研究 Langmuir等温吸附模型能最好的拟合一元溶液中自由香菇吸附铅的热力学过程，相关系数为R20.9939，其次是Freundlich模型，R2 0.9391: Freundlich模型能更好地描述一元溶液中香菇吸附镉的热力学过程，R20.9993，其次是Langmuir模型，R2 0.9391。Freundlich等温吸附模型适合描述固定香菇吸附铅和镉的热力学过程，R2分别达到0.9587和0.9823。Freundlich模型拟合的结果kCd0.4310k2Pb-固定0.785，k2Cd-自由1.253> k2Cd-固定0.213，固定后的香菇吸附铅和镉的速率有所减慢。吸附速率常数k2Pb-自由1.324>k2Cd-自由1.253，k2Pb- 固定0.781>k2Cd-固定0.213，香菇在固定前和固定后吸附铅的速度比吸附镉的快。 (3)扫描电镜观察 香菇吸附铅和镉后细胞壁明显增厚，表面有沉淀以及铅的镉晶体出现，PVA-SA固定香菇和PVA-SA小球表面变得密实，有铅和镉的化合物结晶，说明PVA-SA小球和香菇一样也能通过物理性吸附或形成无机沉淀将铅和镉沉淀在表面。 (4)红外光谱分析 光谱曲线的不同和波长的伸缩，显示出自由香菇细胞壁上的-OH和-CO-NH与铅和镉相结合，将金属离子吸附于细胞壁表面。在固定香菇吸收铅和镉的过程中，香菇细胞壁上的官能团-OH、-CO-NH等和PVA发挥了作用。 4 PVA-SA固定香菇可以解吸再生 PVA-SA固定香菇用10 mM盐酸三次洗脱分别再生利用之后，铅和镉的吸附率仍可以分别达到85.24%和69.07%。 5 固定香菇处理实际废水效果明显 用PVA-SA固定香菇吸附处理会理锌矿选矿废水，处理后的废水中铅的去除率为73.11%，含量从1.112 mg/L降至0.299 mg/L；铜的去除率为66.67%，含量从0.033 mg/L降至0.011 mg/L；镉去除率52.38%，镉从0.021 mg/L降至0.001mg/L。可见，在含有多种金属离子的实际废水处理中，PVA-SA固定香菇能有效地去除废水中重金属。 |
| 英文摘要 | Recently, with the development of global economy, water pollution becomes more and more severe. Heavy metal is to endanger extremely large pollution to the ecological environment. In company with the fast development of the metal plating, mining, dying, petrochemical and battery Industries, a great deal of wastewater containing the excessive dangerous heavy metal ions has been discharged into the environment and would endanger the great harm to the environmental ecology and the human health. Technology of immobilized microorganism is one kind of high-effect, fleetnesss, and is able to cut down secondary pollution effectively. This research reports the adsorption performance of immobilized Lentinus edodes residue. 1 Polyvinyl alcohol—Na-alginate is the best material for immobilizing L. edodes Polyvinyl alcohol—Na-alginate (PVA-SA), alginate and agar are used to immobilize L. edodes residue (dead cells) separately, and results show that PVA-SA beads are the best immobilized cells. An orthogonal experiment is done to confirm the optimal immobilized condition: 8%(m/V) PVA+1%(m/V) sodium alginate+3%(m/V) fungus crosslinking reacted with 2% CaCl2 saturated boric acid solution for Pb2+ biosorption , and 5% PVA+1% sodium alginate+3% fungus Cd2+ absorption. 2 Best condition for PVA-SA immobilized L.edodes absorbing Pb2+ and Cd2+ from soluton (1) Cd2+ and Pb2+ biosorption by L.edodes reaches equilibrium within 60 min, with equilibrium quantities qe 1.812 mg/g and 0.844 mg/g respectively, while PVA-SA immobilized L.edodes 3 h and 7 h separately, with qe 0.2008 mg/g and 0.4925 mg/g respectively. (2) As pH of solution increases, biosorption ratio of Pb2+/Cd2+ by L.edodes and PVA-SA immobilized L.edodes gains. Suitable pH rang is 4～7 for Pb2+ biosorption by L.edodes and PVA-SA immobilized L.edodes separately. Suitable pH range for Cd2+ biosorption is 4～7 for PVA-SA immobilized L.edodes and 6～7 for L.edodes respectively. (3) As initial concentration of metal increases from 0 mg/L to 120 mg/L, Pb2+ and Cd2+ biosorption quantities for PVA-SA immobilized L.edodes increase linearly according to initial concentration of metal raises, when initial concentration of metal reaches 120 mg/L, biosorption quantities are 14.874 mg/L for Pb2+ and 5.462 mg/L for Cd2+. While initial concentration of metal changes from 0 mg/L to 60 mg/L, biosorption quantities grow for free L.edodes, then after initial metal concentration is over 60 mg/L, biosorption quantities don’t gain. Under experimental condition, maximum biosorption quantities for free L.edodes are 8.535 MgPb/g and 2.819 MgCd/g. (4) As biomass concentration of free or PVA-SA immobilized L.edodes uprises, Pb2+ and Cd2+ biosorption ratios decrease, which is contrary to the biosorption quantities. (5) When concomitant metal ion concentration is less than 10 mg/L, Pb2+ biosorption ratio decreases for PVA-SA immobilized L.edodes, but increases for L.edodes. When concentration of concomitant ion is over 10 mg/L. Free L.edodes Pb2+ biosorption ratio decreases greatly:Cu2+ greatly induces Pb2+ biosorption quantities (from 80.02% to 16.21%) and Cd2+ brings Pb2+ biosorption quantities down(from 81.02% to 70.65%), contrarily, Cu2+ promotes PVA-SA immobilized L.edodes Pb2+ biosorption ratio from 65.84% to 84.86%, Cd2+ boosts PVA-SA immobilized L.edodes Pb2+ biosorption ratio from 83.32% to 84.15%. Concomitant metal ion(Pb2+/Cd2+) has an adverse effect on Cd2+ biosorption for both free L.edodes and PVA-SA immobilized L.edodes, however the adverse effect is more serious for free L.edodes. According to variance analysis, Concomitant metal ion has an apparent effect on Pb2+ and Cd2+ biosorption for both biosorbents. 3 Preliminary research of Pb2+ and Cd2+ biosorption for PVA-SA immobilized L. edodes on mechanism has been made headway (1) In single-metal solution, Langmuir model best describes L.edodes Pb2+ biosorption isotherm process with R2 0.9939，and the following is Freundlich model with R20.9391. Freundlich model best fits free L.edodes Cd2+ biosorption isotherm, with R2 0.9993, and the number two is Langmuir, with R20.9391. Freundlich model best fits PVA-SA immobilized L.edodes Pb2+ and Cd2+ biosorption isotherm, with R2 0.9587 and 0.9823 separately. Theoretic maximum biosorption quantities qm=2.8321< qm=6.4475(from Langmuir model) indicates: after immobilizing treatment, L.edodes Cd2+ biosorption capacity increases； k=0.3127＜k=0.4310 shows after immobilizing, L. edodes Pb2+ biosorption capacity also increases. (2) In two-metal solution, Dubinin-Radushkevich model best describes Pb2+ isotherm biosorption process in lead-cadmium solution and Cd2+ isotherm biosorption process in cadmium-copper solution, with R2 0.9478 and 0.9020 respectively, as well as qm 8.386 mg/g and 3.662 mg/g separately. Langmuir best describes Pb2+ isotherm biosorption process in lead-copper solution and Cd2+ isotherm biosorption process in cadmium-lead solution, with R2 0.9440 and 0.9291 respectively, as well as qm 25.445 mg/g and 2.679 mg/g separately. . (3) Pseudo-second-order model fits Pb2+ and Cd2+ biosorption kinetics well. Rate constant of Pseudo-second-order model of free L.edodes are k2Pb 1.3241and k2Cd 1.2531，as well as k2Pb0.7805 and k2Cd0.2130 for PVA-SA immobilized L. edodes, that means after immobilizing, metal biosorption progress lowers for L.edodes. (4) According to scanning electronic microscope (SEM) observation: after absorption of metal ion, thickness of L.edodes cytoderm increases, and Pb2+/Cd2+ crystal is found on both L.edodes and PVA-SA immobilized L.edodes, as well as surface of PVA-SA immobilized L.edodes and PVA-SA beads become close-grained. Because cadmium crystal is smaller than lead crystal, surface of PVA-SA immobilized L.edodes and PVA-SA beads after absorbing Cd2+ is more close-grained than the one after absorbing Pb2+. (5) Infrared spectrum analysis shows that L.edodes functional group, such as -OH、-NH and -CO, as well as PVA play an important role on metal biosorption. 4 Reuse of PVA-SA immobilized L. edodes Pb2+ and Cd2+ biosorption ratios for PVA-SA immobilized L.edodes still reaches 85.24% and 69.07% separately, after three times of regeneration by using 10 mMHCl. 5 Good performance on practical wastewater treatment by PVA-SA immobilized L. edodes Using PVA-SA immobilized L.edodes to remove metal of mill run wastewater from Huili zinc ore: Pb2+ biosorption ratio reaches 73.11%, Cu2+ 66.67% and Cd2+ 52.38%. |
| 学科主题 | 微生物学 |
| 语种 | 中文 |
| 公开日期 | 2010-10-13 |
| 分类号 | O65;O64 |
| 源URL | [http://ir.imde.ac.cn/handle/131551/2167]  |
| 专题 | 成都山地灾害与环境研究所_成都山地所知识仓储（2009年以前） |
| 推荐引用方式 GB/T 7714 | 马培. 固定香菇废弃菌柄对铅和镉的生物吸附研究[D]. 成都. 中国科学院水利部成都山地灾害与环境研究所. 2009. |
入库方式： OAI收割
来源：成都山地灾害与环境研究所
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