响应面法优化改性香蕉皮对Pb~(2+)的吸附研究

用海南本土天然农林废弃物香蕉皮制备的改性吸附剂,来研究其对废水中重金属铅离子的吸收效果。选用吸附剂用量、吸附时间、Pb~(2+)初始浓度和溶液pH等4个单因素的影响实验,在此基础上对上述4种因素采用Box-Behnken响应面优化设计和实验。结果表明,通过响应面设计分析得到改性香蕉皮吸附剂吸附废水中重金属铅离子的最佳条件为:吸附时间为48 min,吸附剂用量为3 mg/L,Pb~(2+)初始浓度为5.5 mg/L,pH值6,在此条件下Pb~(2+)吸附率达到最大值96.90%,接近于理论值96.97%;吸附时间、Pb~(2+)初始浓度以及吸附时间和Pb~(2+)初始浓度的交互作用对Pb~(2+)吸附率影响极显著(P0.001),溶液pH对Pb~(2+)吸附率影响显著(P0.05);二次响应面模型的P值小于0.000 1。该模型的回归方程极显著,可用来分析改性香蕉皮吸附剂对Pb~(2+)的吸附。     

四种吸附剂材料对镉去除及硬水软化的研究

以核桃壳和杏仁壳为原料, 经高温热解成生物炭再利用酸、碱修饰对其进行改性制备成吸附剂材料, 同时以矿物吸附剂(蛭石)和竹炭作为对比材料, 比较了四种改性吸附剂对镉(Cd), 以及对硬水中钙(Ca²⁺)、镁(Mg²⁺)的吸附性能, 考察了吸附剂投加量对 Cd 去除和硬水软化处理效果的影响, 初步探讨了吸附机制。结果表明: 果壳生物炭经酸碱改性后吸附能力显著提升。竹炭和杏仁壳炭对 Cd 的吸附效果相当(去除率分别为 99.2%, 99.1%), 核桃壳炭次之(93.8%),蛭石对 Cd 的去除受 Cd 浓度影响较大, 而杏仁壳可以净化不同程度 Cd 污染废水。核桃壳和杏仁壳炭对 Ca²⁺和 Mg²⁺的吸附能力强, 二者在最小投加量(1 g)时即可将水的硬度降至饮用水标准值(450 mg·L^-1, 以 CaCO₃计)以下, 对 Ca²⁺、Mg²⁺的去除率最高可达 83.6%, 而竹炭和蛭石对硬...     

酵母菌Y17吸附Cu2+的影响因素及吸附机理研究

以高效吸附Cu2+的酵母菌Y17为材料, 对其吸附Cu2+过程中的主要影响因素, 包括溶液pH、Cu2+初始浓度、菌体添加量、吸附时间和温度以及吸附机理进行了探讨。结果表明, 对吸附过程影响较大的因素依次为吸附液pH值、Cu2+初始浓度、菌体添加量和吸附时间。正交试验得到最佳吸附条件为溶液pH5.0, 吸附时间40 min, 加菌量5.0 g湿菌/L时, 对初始浓度为8 mmol/L的Cu2+达到最佳吸附率为82.7%。通过对Y17菌体不同处理及解吸实验, 初步确定Y17吸附Cu2+的位点在细胞壁, 细胞壁表面的-NH2, -COOH基团在其吸附过程中起着重要作用。     

甘蔗渣接枝四乙烯五胺制备治理印染废水的新型吸附剂

论文通过在甘蔗渣(sugarcane bagasse,SB)中引入四乙烯五胺获得改性甘蔗渣(modified sugarcane bagasse,MSB),制备出对有机染料伊红和重金属离子Cu²⁺、Cr³⁺均有较好吸附能力的吸附剂,并研究了pH、温度、初始浓度等因素对吸附的影响.结果表明当伊红溶液pH为6时,MSB的吸附量比SB提高了18倍,对金属Cu²⁺ 、Cr³⁺的吸附量也大大高于SB.染料伊红的吸附过程可以用Langmuir 型吸附等温线较好地模拟,由方程可得25℃下伊红的最大吸附量为399.04 mg·g^-1,MSB对伊红的吸附行为符合伪二级吸附动力学模型.实验结果显示改性甘蔗渣(modified sugarcane bagasse,MSB)是一种吸附性能优异的吸附剂,用于处理印染废水与制革废水有较好的应用前景.     

改性橙皮生物吸附剂的制备及对Pb(Ⅱ)的吸附研究

研究了橙皮对Pb~(2+)的吸附,分别采用H_3PO_4、NaOH、无水乙醇-NaOH、CaCl_(2 )-无水乙醇-NaOH等溶液对橙皮进行改性。探讨了吸附时间、吸附剂用量、吸附温度和溶液酸度对Pb~(2+)吸附效果的影响。并采用扫描电镜和红外光谱对改性橙皮形貌及其吸附Pb~(2+)前后进行表征。结果表明:四种改性橙皮中,以CaCl_(2 )-无水乙醇-NaOH为改性剂制备的改性橙皮对Pb~(2+)吸附效果最好;吸附时间120 min时,改性橙皮吸附剂对Pb~(2+)的吸附已达到饱和,最佳吸附温度为40℃,最佳吸附溶液酸度为pH=5.0;当Pb~(2+)初始浓度为200 mg/L时,吸附剂最佳投入量为0.15 g,此时吸附率达94.43%,吸附量为126.17 mg/g。改性橙皮对Pb~(2+)的吸附方式符合准二级动力学模型,通过Langmuir等温吸附方程模拟,改性橙皮的最大吸附量为156.98 mg/g。改性橙皮是性能良好、可重复使用、安全环保的生物吸附剂。     

一株耐铅菌株NY-3的分离鉴定及其吸附特性研究

目的:以天津滨海近岸沉积物为材料,进行耐铅优势菌株的分离鉴定,探讨影响菌株铅吸附的因素。方法:通过生理生化特征、16S rDNA序列相似性分析对菌株进行初步鉴定,考察pH值、吸附剂投加量、Pb~(2+)的初始浓度、吸附时间等不同条件下菌株对Pb~(2+)的吸附效果。结果:分离出一株耐铅菌株NY-3,鉴定为Oceanimonas sp.,菌株最大耐Pb~(2+)浓度为300 mg/L。在pH值为6、菌体投加量1 g/L、Pb~(2+)初始浓度为100 mg/L时,吸附时间为60 min,菌株对Pb~(2+)的吸附率达94.16%。NY-3对Pb~(2+)的吸附过程符合Langmuir等温模型(R~2=0.9978),动力学数据拟合准二级动力学模型(R~2=0.9997)。结论:菌株NY-3对铅具有较好的吸附效果,可用于重金属污染的微生物修复。     

废啤酒酵母吸附水溶液中Cu2+的性能及机理研究

用废啤酒酵母吸附水溶液中Cu2+,考察了溶液pH值、Cu2+浓度和吸附时间对Cu2+吸附的影响。结果表明：废啤酒酵母吸附Cu2+在4-6个小时内达到吸附平衡,酸性条件利于吸附,以pH为5时最佳,吸附等温曲线符合Langmuir模式。用电位滴定及FTIR分析的方法确定生物吸附剂主要含有磺酸基、羧基及氨基等功能团。生物吸附剂对Cu2+的吸附以单分子层的化学吸附为主,功能团在不同的pH条件下呈现不同的电离性能,在吸附过程中发挥重要作用。     

竹炭对校园湖泊水的净化研究

研究了竹炭对校园湖泊水的净化吸附性能,通过测定竹炭粒径、竹炭用量、吸附时间、温度、pH等对吸附的影响,为竹炭在校园湖泊水源净化处理中的应用提供依据。实验结果表明,竹炭粒径越小,竹炭用量越多,竹炭吸附的时间越长,净化效果越好;吸附温度在10～30℃效果明显;水源的pH值对吸附净化的影响很小。     

拟康宁木霉对甲基橙废水的酶促降解研究

利用驯化获得的拟康宁木霉菌(Trichoderma koningii)处理甲基橙废水,以脱色率为指标探讨了反应时间、初始甲基橙浓度、pH、葡萄糖用量、不同培养时间等培养因素对拟康宁木霉生长前期降解甲基橙废水效果的影响;在较优条件下以脱色率为指标,探讨了酶在pH、温度、酶液投加量、初始甲基橙浓度、反应时间等条件下的酶促降解反应;并通过正交试验验证其脱色降解甲基橙染料的最佳反应条件,为染料废水的处理提供试验基础。试验表明,培养过程中拟康宁木霉菌降解甲基橙废水的最适条件为初始甲基橙浓度30 mg/L,培养时间72 h,葡萄糖浓度25 g/L,pH 6.5。在较优培养条件下提取的酶,在酶液投加量为0.6 mL,温度为25℃,pH为7.0,处理时间为6 h的处理条件下,其降解率可达85.48%,脱色效果较明显。本研究为拟康宁木霉对甲基橙染料废水的酶促降解条件提供了参考。     

龙须菜几株附生细菌对铜离子吸附性能的比较

重金属污染和富营养化是沿岸海域的主要污染形式, 造成沿海生态功能的退化。在重金属污染区域往往伴随着富营养化现象。本文对分离来自电镀废水中铜污染海域内的龙须菜体表的附生微生物对Cu2+的生物吸附进行试验, 分析和比较这些微生物对Cu2+的生物吸收性能。共分离到6株优势附生细菌：人苍白杆菌GF-S1、杀鲑气单胞菌GF-S2、莱拉微球菌GF-S3、纹带棒杆菌GF-S4、假交替单胞菌GF-S5和弗氏弧菌GF-S6。经对Cu2+的生物吸附试验发现, GF-S2效果最好, GF-S6最差, 其余间于这两者之间。对GF-S2、GF-S4和GF-S6进行了最佳吸附时间和pH筛选, 以及使用不同化学试剂对细菌Cu2+吸附的影响试验。结果显示：最佳吸附时间在40 min~60 min, pH介于4~5对GF-S2、GF-S4吸附Cu2+的效果较好; HCl处理导致GF-S2丧失吸附能力, NaOH和乙醇能提高其吸附性能; 3种试剂都能较大地提高GF-S4和GF-S6的吸附性能, 尤其对GF-S4经处理后, 对环境中的Cu2+的去除率得以大幅度提高, 去除较彻底。     

Effects of manufacturing conditions on the adsorption capacity of heavy metal ions by Makino bamboo charcoal

The objective of this study was to investigate the effects of manufacturing conditions on the adsorption capacity of heavy metal ions by Makino bamboo charcoal. Results show that the specific surface area and iodine number of bamboo charcoal activated at 900 degrees C were larger than those of bamboo charcoal activated at 800 degrees C. The specific surface area of bamboo charcoal activated at 800 degrees C by carbon dioxide was larger than that of charcoal activated by steam. However, a contrary result was observed when the activation temperature was 900 degrees C. The total volume and proportion of micropores in bamboo charcoal activated by carbon dioxide were greater than those in the other sample groups. However, the total volume and bulk volume of meso- and macropores, and average pore diameter for bamboo charcoal activated by steam were greater than those in the other sample groups. Using 5g bamboo charcoal (10-30 mesh) with a soaking time of 24h, a better adsorption effect on Pb2+ (100%), Cu2+ (100%), and Cr3+ (88-98%) was found. However, medium frequencies were observed for the adsorption of Cd2+ (40-80%) and Ni2+ (20-60%). Very limited adsorption of As5+ was detected in this study. For the same charcoal grain sizes, the adsorption capacity of 0.5g of charcoal was better than that of 0.1g. The improved adsorption effect of the sample group activated by steam was compared with the sample group activated by carbon dioxide.     

Preparation of poly(methyl methacrylate)–grafted Hyparrhenia hirta for methyl red removal from colored solutions

Poly(methyl methacrylate)–grafted Hyparrhenia hirta (PMMA-g-Hh) biopolymer was prepared through radical polymerization using potassium persulfate (KPS) and applied in adsorption of methyl red from colored solutions. Solvent amount, initiator concentration, monomer concentration, temperature, and reaction time were the reaction parameters investigated for grafting. The biopolymer was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and x-ray diffraction spectroscopy (XRD). The adsorption process was investigated with respect to pH, contact time, initial concentration, adsorbent dosage, and temperature. The optimum adsorption parameters were pH 6, contact time 90 min, adsorbent dosage 0.6 g, and initial concentration 50 mg/L. The Langmuir adsorption model best fitted the adsorption process, with maximum adsorption capacities of 19.95, 6.89, and 4.02 mg/g at adsorbent dosages of 0.2, 0.6, and 1.0 g, respectively. The pseudo-second-order model described the kinetics data better. The adsorption process was physical, spontaneous, and endothermic. The adsorbent was still active after 10 adsorption-desorption cycles, showing its suitability for use in colored solutions treatment.     

Removal of hexavalent chromium using distillery sludge

Batch mode experiments were conducted to study the removal of hexavalent chromium from aqueous and industrial effluent using distillery sludge. Effects of pH, contact time, initial concentration and adsorbent dosage on the adsorption of Cr(VI) were studied. The data obeyed Langmuir and Freundlich adsorption isotherms. The Langmuir adsorption capacity was found to be 5.7 mg/g. Freundlich constants K(f) and n were 2.05 [mg/g(L/mg)(n)] and 3.9, respectively. Desorption studies indicated the removal of 82% of the hexavalent chromium. The efficiency of adsorbent towards the removal of chromium was also tested using chromium-plating wastewater.     

Adsorption of cationic dye from aqueous solutions by date pits: Equilibrium,kinetic, thermodynamic studies,and batch adsorber design

The retention profile of methylene blue from aqueous solutions onto the solid adsorbent date pits has been investigated in a batch system. The characterization and adsorption efficiency for methylene blue was evaluated using date pits. Fourier Transform Infra-Red, Scanning Electron Microscope, Brunauer–Emmett–Teller analysis were performed to determine the characteristics of the material. The effect of contact time, initial dye concentration, adsorbent dosage, temperature, and solution pH were investigated. The adsorption was found to increase with increasing time, decreasing concentration of dye, decreasing temperature and increasing dosage up to equilibrium values which was 20 min, 25°C, and 0.1 g adsorbent, respectively. The adsorption was favorable at high and low pH (pH 3, pH 7). The adsorption equilibrium data were best fitted by Freundlich isotherm. The adsorption kinetics was found to follow the pseudo second order kinetic model. Thermodynamic parameters such as free energy, enthalpy, and entropy were calculated and found to be ?4.6 kJ/mole, ?7.9 kJ/mole, and ?11.8 kJ/mole, respectively. The thermodynamic parameters of the uptake of methylene blue onto the date pits indicated that, the process is exothermic and proceeds spontaneously at low temperature. A single stage batch adsorber was designed for adsorption of methylene blue by Date Pits based on optimum isotherm.     

Gellan gel beads containing magnetic nanoparticles: An effective biosorbent for the removal of heavy metals from aqueous system

This study describes an efficient adsorbent consisting of magnetic Fe₃O₄ and gellan gum, which couples magnetic separation with ionic exchange for heavy metal removal. Adsorption kinetics analysis showed that the adsorption capacities were in an order of Pb²⁺ > Cr³⁺ > Mn²⁺. Different experimental parameters studies indicated that adsorbent dosage, initial metal concentration, temperature and initial pH played important roles in adsorption process. Additionally, the Freundlich model gave a better fit to the experimental data than the Langmuir model. Chemical analysis of calcium ions released into the bulk solutions demonstrated that carboxyl group is critical for binding Pb²⁺, Mn²⁺ and Cr³⁺. Furthermore, a high desorption efficiency was obtained by sodium citrate.     

The Effect of Bamboo Charcoal Application on Soil Nutrients and Heavy Metals in Rice

Soil heavy metal pollution is becoming more and more serious. Biomass charcoal application can play an important role in alleviating the toxicity of heavy metals in soils. Compared with other biochar, bamboo charcoal has more unique properties and may have a unique effect on heavy metal pollution. Zhejiang Province of Southeastern China is rich in bamboo resources. However, few studies related to bamboo charcoal application for heavy metal remediation in farmland were reported. In this study, four treatments with different amounts of bamboo charcoal application were set up through a field experiment, namely BC0 (no bamboo charcoal application), BC1 (2500 kg⋅ha⁻¹), BC2 (5000 kg⋅ha⁻¹), and BC3 (10000 kg⋅ha⁻¹), and each treatment was replicated three times. The results showed that (1) The application of bamboo charcoal significantly increased the soil pH and organic matter content. Compared with BC0, the pH and organic content of BC3 increased by 7.4% and 17.4% (P < 0.05) respectively. (2) The HCl-extractable Cd content of paddy soil in the BC1 treatment was significantly lower than other treatments (P < 0.05), and decreased by 15.3%, compared with BC0. The soil HCl-extractable Zn and Cu content did not differ significantly between treatments (P > 0.05). (3) With the increase of bamboo charcoal application, the Cd content in rice gradually decreased, the BC3 treatment significantly decreased by 39.0% (P < 0.05), and the Zn and Cu contents in rice did not differ significantly between treatments (P > 0.05), compared with BC0. (4) Soil pH, organic matter and Cd in rice seeds were significantly negatively correlated (P < 0.01). The heavy metal content in rice does not change with the change of heavy metal content with HCl-extractable state in soil. It means bamboo charcoal does not reduce heavy metal content in rice by simply declining the heavy metal content with HCl-extractable state. The mechanism of action is relatively complicated, and further study is needed.     

The adsorption of copper(II) ions on to dehydrated wheat bran (DWB): determination of the equilibrium and thermodynamic parameters

The adsorption of copper(II) ions on to dehydrated wheat bran (DWB), a by-product of the flour process, was investigated as a function of initial pH, temperature, initial metal ion concentration and adsorbent dosage. The optimum adsorption conditions were initial pH 5.0, initial copper concentration 100 mg l⁻¹, temperature 60 °C and adsorbent dosage 0.1 g. The adsorption equilibrium was described well by the Langmuir isotherm model with maximum adsorption capacity of 51.5 mg g⁻¹ of copper(II) ions on DWB. The observation of an increase in adsorption with increasing temperature leads to the result that the adsorption of copper(II) ions on DWB is endothermic in nature. The thermodynamic parameters such as enthalpy, free energy and entropy changes were calculated and these values show that the copper(II)-DWB adsorption process was favoured at high temperatures.     

粗毛栓菌和蜡状芽孢杆菌及其共固定菌对Pb2+的吸附

将粗毛栓菌菌丝球与蜡状芽孢杆菌共固定为共固定菌.以粗毛栓菌菌丝球、蜡状芽孢杆菌和共固定菌为研究对象,测定不同吸附时间、初始pH、吸附剂浓度和Pb²⁺浓度对3种生物吸附剂吸附Pb²⁺的影响,并将3种生物吸附剂吸附Pb²⁺前后的红外吸收光谱进行分析比较.结果表明： 在吸附剂浓度为2 g·L^-1、pH为5.0、Pb²⁺浓度为50 mg·L^-1条件下对Pb²⁺吸附1 h效果良好,其吸附率分别为71.7%、91.0%和96.9%.生物吸附剂红外光谱主要由蛋白质、碳水化合物和含硫、磷酸基团的吸收带组成,表明对Pb²⁺吸附起主要作用的官能团是羟基、羧基、磷酸基和含硫基团.     

Efficient Removal of Co2+ from Aqueous Solution by 3-Aminopropyltriethoxysilane Functionalized Montmorillonite with Enhanced Adsorption Capacity

To achieve a satisfactory removal efficiency of heavy metal ions from wastewater, silane-functionalized montmorillonite with abundant ligand-binding sites (-NH₂) was synthesized as an efficient adsorbent. Ca-montmorillonite (Ca-Mt) was functionalized with 3-aminopropyl triethoxysilane (APTES) to obtain the APTES-Mt products (APTES_1.0CEC-Mt, APTES_2.0CEC-Mt, APTES_3.0CEC-Mt, APTES_4.0CEC-Mt) with enhanced adsorption capacity for Co²⁺. The physico-chemical properties of the synthesized adsorbents were characterized by spectroscopic and microscopic methods, and the results demonstrated that APTES was successfully intercalated into the gallery of Ca-Mt or grafted onto the surface of Ca-Mt through Si-O bonds. The effect of solution pH, ionic strength, temperature, initial concentrations and contact time on adsorption of Co²⁺ by APTES-Mt was evaluated. The results indicated that adsorption of Co²⁺ onto Ca-Mt, APTES_1.0CEC-Mt and APTES_2.0CEC-Mt can be considered to be a pseudo-second-order process. In contrast, adsorption of Co²⁺ onto APTES_3.0CEC-Mt and APTES_4.0CEC-Mt fitted well with the pseudo-first-order kinetics. The adsorption isotherms were described by the Langmuir model, and the maximum adsorption capacities of APTES_1.0CEC-Mt, APTES_2.0CEC-Mt, APTES_3.0CEC-Mt and APTES_4.0CEC-Mt were 25.1, 33.8, 61.6, and 61.9 mg·g^-1, respectively. In addition, reaction temperature had no impact on the adsorption capacity, while both the pH and ionic strength significantly affected the adsorption process. A synergistic effect of ion exchange and coordination interactions on adsorption was observed, thereby leading to a significant enhancement of Co²⁺ adsorption by the composites. Thus, APTES-Mt could be a cost-effective and environmental-friendly adsorbent, with potential for treating Co²⁺-rich wastewater.