固定食用菌加工废弃物对废水中重金属Cu2+的吸附性能

用聚乙烯醇-海藻酸钠(PVA-SA)将金针菇(Flammulina velutipes)、毛木耳(Auricularia polytricha)、杏鲍菇(Pleurotus eryngii)和平菇(Pleurotus ostreatus)加工废弃物固定制成吸附小球,研究初始p H值、反应时间对Cu~(2+)吸附的影响及吸附特性,并应用到实际废水的处理中。结果表明:固定金针菇、毛木耳、杏鲍菇和平菇废弃物吸附小球的最大吸附率分别为81.3%、60.8%、42.8%和50.0%;伪二级动力学模型比颗粒内扩散模型能更好地描述固定食用菌加工废弃物吸附小球对Cu~(2+)的吸附过程;固定金针菇、毛木耳和平菇废弃物吸附小球的等温吸附过程与Langmuir等温模型拟合度高,吸附过程主要是单层吸附,固定杏鲍菇废弃物小球的等温吸附过程则更符合Freundlich等温模型;扫描电镜(SEM)分析显示,固定金针菇废弃物吸附小球吸附Cu~(2+)后,细胞壁增厚,细胞壁上形成了明显的Cu~(2+)无机沉淀或晶体,表现为物理性吸附。研究表明,固定金针菇废弃物吸附小球对自然废水中Cu~(2+)的去除率为73.11%,具有一定的实际应用价值。

Biosorption function of Cu2+ from wastewater by immobilized edible fungi residue

To find a comparatively cheap-available biosorption material for Cu2 + removal from the wastewater,this paper has adopted the polyvinyl alcohol-Na-alginate(PVA-SA) to immobilize Flammulina velutipes,Auricularia polytricha,Pleurotus eryngii and Pleurotus ostreatus residues as adsorbents,respectively.For the purpose,we have tested the concentration of Cu2+ by using the inductively coupled plasma optical emission spectrometry (ICP-OES).At the same time,we have also made an investigation of the effects of the initial pH value and the contact time on the Cu2+ removing behavior.As a result,we have found that the maximum biosorption ratio of F.velutipes,A.polytricha,P.eryngii and P.ostreatus residues should be taken in 81.3％,60.8％,42.8％ and 50.0％,respectively,under the optimum conditions(that is,in pH value of 6.0,and,the contact time of 120-180 min).We have also noticed that Cu2+ adsorption process by F.velutipes,A.polytricha,P.eryngii and P.ostreatus residues could be well described with the pseudo-second-order model with R2 of 0.997 1,0.998 8,0.999 1 and 0.995 8,respectively.In addition,the experimental data of the aforementioned adsorbents produced by F.velutipes,A.polytricha and P.ostreatus residue are well fitted for Langmuir isotherm model,on the condition when its theoretical biosorption quantities can be worked out at about 7.230 4 mg/g,6.571 3 mg/g and 4.513 6 mg/g,which turns to be very close to the experimental data,indicating the monolayer adsorption has been dominating process.Besides,the data of P.eryngii residue prove to be well fitted with Freundlich equation while R2 should be 0.932 2.Furthermore,the SEM analysis demonstrates that the thickened F.velutipes cell walls formed by Cu2+ adsorption turn out to be remarkably crystal,suggesting that the adsorption process has been done in dependence on the physical adsorption.Thus,when F.velutipes residue is used to remove Cu2+ in the wastewater with the removal ratio of 73.11％,the process can be expected to provide an effective biological adsorbent of the low concentrated Cu2+ from the wastewater under operation.