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941.
Four materials, sodium carboxymethylcellulose (Na-CMC), sodium alginate (SA), polyvinyl alcohol (PVA), and chitosan (CTS), were prepared as supports for entrapping fungus Aspergillus fumigatus. The adsorption of synthetic dyes. Reactive Brilliant Blue KN-R, and Reactive Brilliant Red K-2BP, by these immobilized gel beads and plain gel beads was evaluated. The adsorption efficiencies of Reactive Brilliant Red K-2BP and Reactive Brilliant Blue KN-R by CTS immobilized beads were 89.1% and 93.5% in 12 h, respectively. The adsorption efficiency by Na-CMC immobilized beads was slightly lower than that of mycelial pellets. But the dye culture mediums were almost completely decolorized in 48 h using the above-mentioned two immobilized beads (exceeding 95%). The adsorption efficiency by SA immobilized beads exceeded 92% in 48 h. PVA-SA immobilized beads showed the lowest adsorption efficiency, which was 79.8% for Reactive Brilliant Red K-2BP and 92.5% for Reactive Brilliant Blue KN-R in 48 h. Comparing the adsorption efficiency by plain gel beads, Na-CMC plain gel beads ranked next to CTS ones. SA and PVA-SA plain gel beads hardly had the ability of adsorbing dyes. Subsequently, the growth of mycelia in Na-CMC and SA immobilized beads were evaluated. The biomass increased continuously in 72 h. The adsorption capacity of Reactive Brilliant Red K-2BP and Reactive Brilliant Blue KN-R by Na-CMC immobilized beads was 78.0 and 86.7 mg/g, respectively. The SEM micrographs show that the surface structure of Na-CMC immobilized bead is loose and finely porous, which facilitates diffusion of the dyes. 相似文献
942.
探析培养转速与镁离子浓度对氧化亚铁硫杆菌生物合成次生铁矿物的影响对酸性矿山废水(AMD)治理具有一定的工程指导意义.本研究通过摇瓶实验,研究了Mg2+浓度分别为48与4.8 mg·L-1,其它元素组成与富含Fe与SO2-4的9K液体培养基一致的体系在180 r·min-1与100 r·min-1转速条件下氧化亚铁硫杆菌催化合成次生铁矿物过程.考察了不同次生铁矿物合成体系pH、Fe2+氧化率、总Fe沉淀率及次生铁矿物矿相等相关指标.研究结果表明,在180 r·min-1的培养条件下,Mg2+浓度分别为4.8与48 mg·L-1两体系培养48 h后,pH从原始的2.50分别降低至2.07与2.12,Fe2+均可在48 h内实现完全氧化.Fe2+完全氧化时,Mg2+浓度为4.8 mg·L-1体系总Fe沉淀率为37.4%,合成的次生铁矿物均匀分散于溶液中,而Mg2+浓度为48 mg·L-1体系中,总铁沉淀率仅为31.7%,且70%的矿物牢固粘附于摇瓶底部.培养转速为100 r·min-1时,Mg2+浓度分别为4.8与48 mg·L-1两体系经过72 h培养后,pH均从原始的2.50降低至2.21与2.17.Fe2+需要72 h才能被完全氧化,两体系总Fe沉淀率分别仅为21.3%与23.0%,产生的次生铁矿物几乎全部牢固粘附于摇瓶底部.本研究所有体系产生的次生铁矿物均为黄铁矾与施氏矿物的混合物.研究结果可为生物合成次生铁矿物工艺的优化及其在酸性矿山废水治理领域的有效应用提供必要的参数支撑. 相似文献
943.
944.
一种高效微生物絮凝剂产生菌的筛选及培养基优化 总被引:43,自引:1,他引:43
从某自来水处理厂的活性污泥中筛选得到了一株稳定高效的微生物絮凝剂产生菌MBF-33,所产絮凝剂对高岭土悬浮液体系有较好的絮凝作用.通过培养基优化,对高岭土的絮凝率从81.3%提高到95%.实验结果表明:(1)适宜的单一碳源为25 g·L-1葡萄糖;(2)复合碳源效果优于单一碳源,适宜的复合碳源为蔗糖5 g·L-1,葡萄糖20 g·L-1;(3)无机氮不利于该菌生长,适宜的氮源为单一有机氮,为1.5 g·L-1蛋白胨;(4)0.2 g·L-1的MgSO4有利于菌生长,但不利于絮凝剂产生. 相似文献
945.
946.
947.
Aleah Bowie Wen Zhou Jingzhi Tan Philip White Tara Stoinski Yanjie Su Brian Hare 《Conservation biology》2022,36(4):e13922
Forests are essential common-pool resources. Understanding children's and adolescents’ motivations for conservation is critical to improving conservation education. In 2 experiments, we investigated 1086 school-aged children and adolescents (6–16 years old) from the United States, China, and the Democratic Republic of Congo. Testing participants in groups, we assessed their motivation for conservation based on collective-risk common-pool goods games in which they were threatened with losing their endowment unless the group donation exceeded a threshold needed to maintain the forest. Extrinsic motivations, rather than intrinsic, tended to lead to successful cooperation to maintain a forest. Certainty of losing individual payoffs significantly boosted successful cooperative conservation efforts across cultures (success rates were 90.63% and 74.19% in the 2 risk-extrinsic conditions, and 43.75% in the control condition). In U.S. participants, 2 extrinsic incentives, priming discussions of the value of forests and delay of payoffs as punishment, also increased success of cooperative conservation (success rates were 97.22% and 76.92% in the 2 extrinsic-incentive conditions, and 29.19% and 30.77% in the 2 control conditions). Conservation simulations, like those we used, may allow educators to encourage forest protection by leading groups to experience successful cooperation and the extrinsic incentives needed to motivate forest conservation. 相似文献