菌株RB5-M1脱色活性黑5的动力学及固定化条件

通过研究嗜水气单胞菌RB5-M1菌株对活性黑5的脱色过程,探讨了菌株脱色不同初始浓度的活性黑5的动力学模型,并从机械强度、包埋量和渗漏量3个方面,对菌株的固定化条件进行了优化。结果表明,当初始染料浓度为50、100、150、200、250和300 mg/L时,菌株脱色活性黑5的动力学过程均更为符合Monod零级反应模型。当冷却温度为30℃、PVA与海藻酸钠浓度比为10∶1、氯化钙浓度为2%、明胶浓度0.2%时,可以获得机械强度较好、包埋量较多的固定化颗粒。当氯化钙浓度2%、明胶浓度0.3%、PVA与海藻酸钠浓度9∶2、冷却温度20℃,可获得渗漏量较少的固定化颗粒。     

包埋活性污泥和反硝化污泥全程硝化反硝化脱氮

将活性污泥和驯化所得的反硝化污泥菌泥按适当比例混合后,用聚乙烯醇(PVA)将其包埋,制成直径为3～4mm的颗粒小球.以模拟废水为处理对象,在流化床反应器内进行实验.结果表明,包埋颗粒小球对氮素和COD的去除效果良好,当包埋颗粒填充率为7％～8％(体积比),控制其他条件,12h的NH4+-N和TN去除率均在95％以上,对COD的去除率大于95％.整个过程中NO2--N未见明显积累,因此为全程硝化反硝化脱氮.最后,通过单因素实验得出的最佳温度、pH值和溶解氧浓度分别为30℃、7.5和4 mg/L.     

固定化小球藻与活性污泥的共生系统处理含锌废水

研究固定化小球藻与活性污泥的共生系统对含锌废水中Zn2+的去除效果,分析菌藻状态、初始Zn2+浓度、pH、固定化菌藻小球投加量和菌藻体积比等5个因素对固定化菌藻共生系统去除Zn2+的影响。结果表明,固定化活性污泥、固定化小球藻和固定化菌藻对Zn2+的去除效果均优于悬浮小球藻,其中固定化菌藻对Zn2+的去除效果最好;废水中初始Zn2+浓度小于100 mg/L时,固定化菌藻系统对废水中Zn2+的去除率达到90.5%;固定化菌藻系统去除废水中Zn2+的最佳条件是:初始Zn2+浓度为80 mg/L,pH=7,固定化小球投加量为80 mL,菌藻体积比为1∶2。     

固定化微生物修复石油污染土壤特性试验

利用梯度稀释法分离筛选原油降解混合菌,采用吸附法将混合菌固定在砾石和草炭土上,探讨固定化混合菌对土壤石油烃的去除效果。结果表明:分离得到的混合菌8-2,菌群结构简单,石油烃降解率可达52.1%。与砾石相比,草炭土所固定的微生物数量和活性较高,可达1.3×108 cfu/g和0.24A487。草炭土固定的混合菌8-2,修复含油量为30g/kg的污染土壤30d后,石油烃降解率达28.4%,高于游离降解菌的24.3%。固定化载体草炭土在修复过程中起到了微生物缓释剂的作用。     

Synthesis of iron composites on nano-pore substrates: Identification and its application to removal of cyanide

Two types of nano-pore substrates, waste-reclaimed (WR) and soil mineral (SM) with the relatively low density, were modified by the reaction with irons (i.e. Fe(II):Fe(III) = 1:2) and the applicability of the modified substrates (i.e. Fe-WR and Fe-SM) on cyanide removal was investigated. Modification (i.e. Fe immobilization on substrate) decreased the BET surface area and PZC of the original substrates while it increased the pore diameter and the cation exchange capacity (CEC) of them. XRD analysis identified that maghemite (γ-Fe₂O₃) and iron silicate composite ((Mg, Fe)SiO₃) existed on Fe-WR, while clinoferrosilite (FeSiO₃) was identified on Fe-SM. Cyanide adsorption showed that WR adsorbed cyanide more favorably than SM. The adsorption ability of both original substrates was enhanced by the modification, which increased the negative charges of the surfaces. Without the pH adjustment, cyanide was removed as much as 97% by the only application of Fe-WR, but the undesirable transfer to hydrogen cyanide was possible because the pH was dropped to around 7.5. With a constant pH of 12, only 54% of cyanide was adsorbed on Fe-WR. On the other hand, the pH was kept as 12 without adjustment in Fe-WR/H₂O₂ system and cyanide was effectively removed by not only adsorption but also the catalytic oxidation. The observed first-order rate constant (k_obs) for cyanide removal were 0.49 (±0.081) h⁻¹. Moreover, the more cyanate production with the modified substrates indicated the iron composites, especially maghemite, on substrates had the catalytic property to increase the reactivity of H₂O₂.     

吸附融合菌的固定化及对铬吸附特性研究

研究了融合菌的固定化方法及吸附特性,结果表明:1.5%海藻酸钠为包埋剂包埋50 g/L融合菌可制成物理和吸附性能较好的固定化吸附剂;40 g/L(约含5 g/L融合菌)的固定化吸附剂对30 mg/L含Cr废水的去除率可达94.54%;当投加量为50 g/L(约含6 g/L融合菌)时,固定化吸附剂可完全去除实际电镀废水(pH:2.67,Cu:1.70 mg/L,Cr:20.62 mg/L,N i:29.97 mg/L,Zn:1.11 mg/L)中的Cu和Cr,且对N i和Zn的去除率也分别达到了48.05%和61.09%;吸附过程符合准二级吸附动力学模型;填充柱工艺适用于固定化吸附剂连续处理含铬废水,当流速为150 mL/h和250 mL/h时填充柱一次稳定处理水量分别为7.2 L和11.5 L,且延长水力停留时间可提高出水水质。     

酸改性壳聚糖载体对漆酶的固定化

利用有机酸改性壳聚糖和交联法制备酸化壳聚糖载体,然后用改性壳聚糖载体固定漆酶。结果表明,甲酸、酒石酸改性壳聚糖的最适条件是壳聚糖与酸的量比分别为100/1(g/mol)、100/0.5(g/mol),戊二醛的浓度分别为1%、2%,缓冲溶液的pH分别为4.4、3.6,反应时间分别为3h、4.5h。两种酸改性的壳聚糖用于漆酶的固定,其酶活都有所提高,尤其用酒石酸改性的壳聚糖载体的效果最好,其酶活提高了57%。     

微生物固定化技术与污水处理

简要介绍了几种常用微生物固定化方法,重点讨论了微生物固定化技术在污水处理方面的应用,并对未来的发展方向进行了展望。     

Cadmium removal mechanistic comparison of three Fe-based nanomaterials: Water-chemistry and roles of Fe dissolution

● nZVI, S-nZVI, and nFeS were systematically compared for Cd(II) removal. ● Cd(II) removal by nZVI involved coprecipitation, complexation, and reduction. ● The predominant reaction for Cd(II) removal by S-nZVI and nFeS was replacement. ● A simple pseudo-second-order kinetic can adequately fit Fe(II) dissolution. Cadmium (Cd) is a common toxic heavy metal in the environment. Taking Cd(II) as a target contaminant, we systematically compared the performances of three Fe-based nanomaterials (nano zero valent iron, nZVI; sulfidated nZVI, S-nZVI; and nano FeS, nFeS) for Cd immobilization under anaerobic conditions. Effects of nanomaterials doses, initial pH, co-existing ions, and humic acid (HA) were examined. Under identical conditions, at varied doses or initial pH, Cd(II) removal by three materials followed the order of S-nZVI > nFeS > nZVI. At pH 6, the Cd(II) removal within 24 hours for S-nZVI, nFeS, and nZVI (dose of 20 mg/L) were 93.50%, 89.12% and 4.10%, respectively. The fast initial reaction rate of nZVI did not lead to a high removal capacity. The Cd removal was slightly impacted or even improved with co-existing ions (at 50 mg/L or 200 mg/L) or HA (at 2 mg/L or 20 mg/L). Characterization results revealed that nZVI immobilized Cd through coprecipitation, surface complexation, and reduction, whereas the mechanisms for sulfidated materials involved replacement, coprecipitation, and surface complexation, with replacement as the predominant reaction. A strong linear correlation between Cd(II) removal and Fe(II) dissolution was observed, and we proposed a novel pseudo-second-order kinetic model to simulate Fe(II) dissolution.     

土壤对钻井废水中有机污染物吸附作用研究

分析了钻井废水中有机污染物在土壤中吸附的机理,对吸附量和有机负荷的关系进行了阐述;针对钻井废水有机污染物在土壤中的吸附和解吸过程进行了实验研究。实验表明:钻井废水中有机污染物在土壤中的吸附量与土壤有机负荷的关系符合初始质量等温线;土壤中天然有机质含量越高,对钻井废水中有机污染物吸附能力越强;土壤对钻井废水中有机污染物具有一定的持久吸附作用;天然有机质含量越高的土壤对钻井废水中有机污染物的持久吸附能力越强。