用枯草芽孢杆菌吸附去除电镀废水中的铜

通过筛选和培育,从某电镀活性污泥中得到一株高效耐Cu2+功能吸附菌,根据菌落形态特征及16S rDNA序列测定和比对,鉴定出该菌株为芽孢杆菌属中的枯草芽孢杆菌(Bacillus subtilis-TR1).研究了用此菌种从电镀废水中吸附去除C u2+,考察了废水初始p H、C u2+初始质量浓度、温度、菌种加入量、培养时间及摇床转速等对C u2+去除率的影响.结果表明:在废水初始p H=5、C u2+初始质量浓度80 m g/L、温度30℃、细菌接种量3 g/L、培养时间48 h条件下,此菌种对Cu2+有较好的吸附去除效果,Cu2+去除率达62.4％,吸附量达4.02 mg/g;主要吸附机制为通过自身表面的功能基团和静电引力,诱导废水中Cu2+发生迁移和离子交换,与表面功能基团结合形成典型非晶相结构配合物,进而将C u2+去除.研究结果为电镀污泥的源头减量提供了一种可用吸附材料,可为电镀废水的微生物处理提供参考.     

青霉素对枯草芽孢杆菌破壁效果研究

[目的]研究枯草芽孢杆菌生长期添加青霉素时的破壁效果.[方法]为使细菌释放出细胞内的有效活性物质,采用青霉素干扰微生物细胞壁形成的方法,研究不同的青霉素添加量对细胞的破壁效果.[结果]通过检测破壁前后菌体光密度变化值得出,在枯草芽孢杆菌的生长期,青霉素添加量对菌体光密度的变化有明显影响,青霉素添加量为25 mg/Kg,作用时间4 h,温度30℃时,光密度变化值(AOD)最高,达0.695,说明此时破壁效果最佳.[结论]青霉素对细胞具有一定的破壁效果,推测根据需要可以适量添加青霉素,使细菌释放出细胞内的物质.     

高炉渣对铬离子的吸附特性研究

采用振荡吸附试验,研究了高炉渣用量、粒度、溶液pH值、吸附时间、溶液初始浓度等因素对去除Cr3 效果的影响。结果表明:高炉渣对溶液中的Cr3 有较强的吸附作用,按铬与高炉渣质量比为1:400投加高炉渣,铬的去除率达到97%以上,完全达到污水综合排放标准。在废水pH值4-12范围内高炉渣能够很好地适应Cr3 初始浓度的变化,对吸附去除Cr3 保持较高而稳定的吸附去除率。由于高炉渣表面带负电,而Cr(Ⅵ)是以阴离子团存在,故其对Cr(Ⅵ)的吸附去除能力远远低于Cr3 的吸附去除能力。     

三聚氰胺对汞离子的吸附性能

三聚氰胺中含有三个自由氨基和三个芳香氮原子,对重金属离子具有很大的吸附潜力。为考察该吸附剂对汞离子的吸附性能,实验分别在不同吸附时间、吸附温度、溶液pH值、汞离子浓度条件下测定三聚氰胺对汞离子的吸附容量和吸附率,结果表明三聚氰胺对汞离子具有良好的吸附性能。在30 ℃温度下,pH 5.0,50 mg三聚氰胺在25 mL 5.430 mg/L氯化汞溶液中对汞离子吸附6 h,测得吸附容量为606 mg/g,吸附率达38.9%,其吸附等温线属于Freundlich型。由于该吸附剂的良好综合吸附性能和廉价优势,使得它在汞离子的分离、富集及含汞废液处理领域具有广阔的应用前景。     

啤酒酵母对镉离子的吸附特性及机理研究

文章在啤酒酵母吸附镉离子试验的基础上,用吸附等温线对吸附特性进行了描述,用Langmuir吸附模型对啤酒酵母的吸附行为进行了评价.并对啤酒酵母吸附镉离子的机理进行了探讨.研究表明:啤酒酵母对Cd2 离子的吸附主要发生在细胞壁,酵母对Cd2 离子的吸附可能与离子交换有关.     

D296交换树脂对氰离子吸附特性研究

采用实际工业含氰废水,通过对比试验研究了氰离子(CN-)在D296强碱阴离子交换树脂Cl型和OH型上的吸附行为,从热力学和动力学方面对交换吸附过程进行了分析,初步探讨了吸附机理。试验结果表明:CN-在D296 Cl型和OH型树脂上的交换吸附是放热过程,同时符合Freundlich等温吸附方程;颗粒内扩散为CN-在D296 Cl型树脂上吸附速率的主要控制步骤,随着含氰废水初始质量浓度的增大,交换吸附量逐渐增大;D296 Cl型对CN-交换吸附性能优于D296 OH型。     

铁锰氧化物对稀土离子的吸附行为研究

采用化学共沉淀法制备铁锰复合氧化物作吸附剂,通过静态和动态吸附实验探究了不同吸附条件对铁锰氧化物吸附稀土离子的影响,对铁锰氧化物吸附稀土离子过程进行了等温吸附模型拟合和吸附动力学、吸附活化能分析,探究了稀土离子在铁锰氧化物上的吸附机理。结果表明,稀土离子在铁锰氧化物上的吸附过程符合Langmuir等温吸附模型;稀土离子在铁锰氧化物上的吸附过程符合准二级动力学模型,属于单层均匀的化学吸附过程,吸附速率控制步骤由化学吸附决定,且温度对吸附动力学影响程度最大;吸附热力学分析表明铁锰氧化物吸附稀土离子是吸热的化学吸附过程,吸附活化能分别为E₍La³⁺)=11.04 kJ/mol、E₍Gd³⁺)=16.85 kJ/mol和E₍Y³⁺)=16.67 kJ/mol;稀土离子与铁锰氧化物上的羟基发生了交换形成了内层络合物,稀土离子取代表面羟基是主要的吸附机制。     

两步控制策略优化生防菌B579芽孢生成条件

[目的]优化生防菌-枯草芽孢杆菌B579芽孢生成的发酵条件,提高芽孢浓度.[方法]采用2步控制策略,即发酵的第1阶段(菌体生长阶段,0-10 h)促进细胞生长,发酵的第2阶段(菌体对数生长后期,芽孢生成阶段,10-30 h)促进芽孢生成,分别考察了培养基初始葡萄糖浓度、发酵pH、第2阶段摇床转速、第2阶段发酵温度对芽孢生成的影响.通过单因素试验确定其水平,在单因素试验基础上进行正交试验优化,确定获得高浓度芽孢的最佳发酵条件.[结果]培养基初始葡萄糖浓度是影响芽孢生成的显著因素,芽孢生成的最佳发酵条件为培养基初始葡萄糖浓度5g/L,发酵pH 7.0,第1阶段的发酵温度37℃,摇床转速180 r/min,约10 h后进入第2阶段,发酵温度提高到40℃,摇床转速调节为200 r/min.发酵30 h,最终获得的芽孢浓度为(9.43±0.15)×10<.8>CFu/ml,芽孢生成率为90.99%,分别是优化前的6.70和2.43倍.[结论]利用两步控制发酵策略可提高生防菌B579芽孢浓度,建立的发酵工艺为生防菌剂的大规模生产奠定了基础.     

向日葵秸杆对铜离子的吸附特征研究

[目的]以寻求廉价而高效的生物吸附材料为目的,研究向日葵秸杆对铜离子的吸附性能.[方法]以向日葵秸杆为主要原料,对含Cu2+的模拟废水进行了吸附试验.[结果]吸附作用受pH值影响明显,在pH值为6.00时,吸附量最大;向日葵秸杆吸附量随温度的升高而增大,Freundlich方程更适合描述Cu2+在向日葵秸杆上的吸附行为;对吸附热力学参数AG、AS、AH的计算表明,吸附反应具有自发性、吸热特性,[结论]向日葵秸杆是一种优良的处理铜离子废水的生物材料.     

针铁矿对重金属离子的吸附作用

对针铁矿合成试验和针铁矿吸附重金属离子进行了研究。试验结果表明，针铁矿可用铁矿废渣获得，通过酸碱中和的方式所获得的针铁矿是微细针状，针铁矿对重金属离子具有强烈的吸附作用，对Cu^2 、Zn^2 和Cd^2 的吸附边界pH值分别为4.3,5.8和7.3，且吸附率最高可达95％以上；尤其对Pb^2 的吸附作用更加强烈，在pH值为3.5时吸附率就达到95％，并且随着pH值的升高吸附率仍在95％以上。研究表明，铁矿废渣可被利用制备针铁矿，针件矿用于含重金属离子污水的处理，具有较好效果。     

Adsorption of neodymium,terbium and dysprosium using a synthetic polymer-based magnetic adsorbent

In this study,a polyamide with methine-thiophene and pyrimidine linkages(poly(pyrimidine-thiophene-amide)(PPTA)) was synthesized.Then,magnetic PPTA(M-PPTA) was synthesized using the hydrothermal technique.The products were analyzed by Fourier-transform infrared spectroscopy(FTIR),nuclear magnetic resonance(NMR),X-ray diffraction(XRD),thermogravimetric analysis(TGA),field-emission scanning electron microscopy(FE-SEM),and a vibrating-sample magnetometer(VSM).The nanocomposite exhibits a saturation...     

Adsorption of dichromate ions on the red mud surface

The possibility of using a red mud (waste of alumina production) as a sorbent of dichromate ions from aqueous solutions is studied. A method for the activation of red mud by hydrochloric acid is proposed. The dependences of the amount adsorbed of dichromate ions on the pH and initial concentration of aqueous solutions are studied.     

腐殖质对重金属离子的吸附作用

采用腐殖质对重金属离子进行了吸附试验。其结果表明 ,腐殖质对重金属离子具有强烈的吸附作用。腐殖质对Cu2 + 、Zn2 + 、Cd2 + 的吸附边界pH值分别为 4 2 ,5 8,7 2 ,吸附率可达 95 %以上 ;对Pb2 + 的吸附作用更加强烈 ,在pH值为 3 5时吸附率就达到 95 %以上 ,并且随着pH值的升高吸附率仍在 95 %以上。腐殖质对 4种重金属离子的吸附能力由强到弱的顺序是Pb2 + >Cu2 + >Zn2 + >Cd2 + 。腐殖质可以用来处理含重金属离子的污水 ,具有过滤快、沉降稳定、效果好的优点 ;也可作为土壤改良剂 ,有效地降低土壤中重金属的含量     

Mutagenic and tumourigenic properties of the spores of Aspergillus clavatus

Spore walls of a sputum-derived isolate of Aspergillus clavatus yielded mutagen(s) when their extracts were fractionally precipitated with ethanol following alkaline hydrolysis. After spores were given by nasal inoculation to 6-8-week-old CF-1 mice, light and electron microscopy of lung sections showed that they had been readily phagocytozed by the polymorphonuclear leucocytes and alveolar macrophages mobilized during early allergic alveolitis in immunized mice. The formation of phagosomes was followed in thioglycollate-stimulated peritoneal macrophages grown in vitro. Unimmunised mice showed a comparable lung reaction, attributed to pulmonary mycotoxicosis, and revealed a rising incidence of lung tumours, from 25% at 2 months from inoculation, to 27.3% at 6 and to 55.5% at 8. Mean numbers of tumours per lung rose from 1.0 to 2.2. Total tumours, including lymphomas, reached a final incidence of 77.7% at 8 months, when control animals were tumour-free. Tumour development correlated with the retention of apparently intact spores within giant cells probably derived from aggregates of alveolar macrophages. The implications of these findings in the light of the known history of human exposure to such spores is discussed.     

Adsorption kinetics of dicyanoaurate and dicyanoargentate ions in activated carbon

A kinetic model describing the adsorption of dicyanoaurate and dicyanoargentate ions in activated carbon has been derived assuming that the dicyanoions adsorbed onto the external surface are in equilibrium with those in solution. This equilibrium may be described by a modified Langmuir-Hinselwood equation as is usual in heterogeneous catalysis systems. Once adsorbed onto the outer surface, the dicyanoions can diffuse toward the inner surface of the particle through the pores of the carbon, or they can be desorbed back to the liquid phase. The two exit stages are fast enough to maintain the outer surface in a pseudostationary state in normal experimental conditions. Finally, the kinetic parameters for the process are determined. The fitting of the model with experimental data is satisfactory and the range of applications is wide. M. SEGARRA and M. FERNáNDEZ, former Graduate Students, and F. ESPIELL     

Synthesis and luminescent properties of terbium complex with 2-amino-4-chlorobenzoic acid

A novel complex [Tb(L)_2(H_2O)_3·H_2O](where L=2-amino-4-chlorobenzoic acid) was synthesized and characterized by a series of analysis. The molecular formula of complex was confirmed by Fourier transform infrared(FT-IR) spectroscopy and thermogravimetric/differential thermogravimetric(TG-DTG) measurements. The optical properties of complex was measured by ultraviolet spectroscopy(UV) and fluorescence spectroscopy(FS). The results indicated that Tb~(3+) in the complex was coordinated by ligand, and the complex emitted bright yellow-green luminescence with main peak at 548.8 nm with excitation at 369.4 nm.     

Relationship between cortex content and properties of Bacillus sphaericus spores

The muramic lactam content of spores of Bacillus sphaericus mutants defective in meso-diaminopimelic acid synthesis increases almost linearly with an increase of meso-diaminopimelic acid concentration in the medium. Since muramic lactam content is a measure of cortex content, the amount of cortex in spores of the mutants can be easily varied by changing the meso-diaminopimelic acid concentration in the medium. Characteristic properties were tested in spores containing different amounts of cortex. Critical amounts of cortex were associated with different spore properties. Refractility and dipicolinic acid accumulation in the spores both required about 20% of the maximum cortex content (although refractility is independent of dipicolinic acid content). For xylene octanol resistance, about 25% of the maximum cortex content was required.     

Adsorption of rare earth ions using carbonized polydopamine nano carbon shells

Herein we reported the structure effects of carbon nano-shells prepared by the carbonization of polydopamine for the adsorption of rare earth elements(REEs) for the first time. Solid carbon spheres, 60 nm carbon shells and 500 nm carbon shells were prepared and evaluated for adsorption and desorption of REEs. The adsorption performance of carbon nano-shells for REEs was far superior to the solid carbon spheres. In addition, the effect of acidity on the adsorption and desorption properties was discussed. The good adsorption performance of the carbon nano-shells could be attributed to their pore structure, specific surface area, and the presence of both amine and carbonyl groups from the grafted dopamine.     

Study on preparation and properties of tannins immobilized chitosan-Ce4+ resins

The tannins immobilized chitosan-Ce⁴⁺ resins (TCCR) were prepared. The optimum conditions on activating and coupling of chitosan resins were obtained by means of orthogonal design experiments. TCCR were characterized by DSC and FT-IR. The adsorption capacity for bovine serum albumin (BSA) of TCCR was investigated. The results show that TCCR have an excellent adsorption capacity for BSA in water, comparing with chitosan-Ce⁴⁺ resins (CCR). The TCCR can be a novel functional material for removal protein in some beverages.