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471.
将磷钨酸、甲醛气体负载于介孔分子筛SBA-15中制备脱氮吸附剂,其中SBA-15、磷钨酸、甲醛的质量比为10∶7∶3.以喹啉、吲哚和咔唑为目标氮化物,二甲苯及二甲苯和十二烷的混合液为溶剂配制模拟含氮油,考察了反应温度、氮化物类型对脱氮反应速率的影响以及磷钨酸、甲醛的脱氮机制.结果表明,磷钨酸可以有效脱除碱性氮化物和低浓度非碱性氮化物,甲醛能强化吸附剂对非碱性氮化物的选择性.在70℃、脱氮吸附剂与高浓度模拟含氮油质量比为2.0∶30.0的条件下,模拟含氮油中的氮化物在90 min内可以被深度脱除.磷钨酸对碱性氮化物的脱除机制为磷钨酸和碱性氮化物间的配合作用和酸碱反应,磷钨酸对非碱性氮化物的脱除机制为氮化物和甲醛在酸催化下缩合反应生成聚合物.反应吸附剂再生回用后的脱氮能力随氮化物碱性的增强而减弱. 相似文献
472.
林可霉素菌(Streptomyces lincolnensis)利用吡唑酮废水的研究 总被引:1,自引:1,他引:0
采用被吡唑酮废液驯化、分离、筛选后的林可霉素菌,并对其在摇瓶上利用吡唑酮废液中的硫酸铵发酵(7 d)生产林可霉素进行了研究。实验结果表明,废液加入培养基体积比都为1∶10,实验1中菌丝代谢和对照比正常,其中还原糖利用最快,在发酵后期为0.24 mg/L,林可霉素起步效价最低为2 100 IU/mL,与对照相比最后发酵效价降低了70 IU/mL;实验2发酵过程pH值偏低,全程为5.86~6.50,氨基氮代谢缓慢为40 mg/100 mL,最后林可霉素效价最低为4 480 IU/mL;实验3中废液在发酵进入48 h中后期的时候补入能促进菌丝体分泌,最后林可霉素为5 180 IU/mL,比对照发酵水平高出8.82%。可见实验3的实验设计有利于林可霉素菌利用吡唑酮废液生产林可霉素,为废物循环利用、变废为宝的可行性作了有意义尝试。 相似文献
473.
Ning Hou Fengzhao Feng Yan Shi Huiming Cao Chunyan Li Zhi Cao Yi Cheng 《Environmental science and pollution research international》2014,21(17):10386-10398
A highly efficient demulsifying strain, LH-6, was isolated from petroleum-contaminated soil and identified as Bacillus cereus by 16S rDNA gene analysis. It achieved 95.61 and 95.40 % demulsifying ratios within 12 h for water-in-oil (W/O) and oil-in-water (O/W) model emulsions, respectively. Fourier transform infrared spectroscopy (FT-IR) and thin-layer chromatography (TLC) detections indicated that the LH-6’s extracellular biodemulsifiers were different types of lipopeptides for the W/O and O/W emulsions. Optimization of the culture medium composition was conducted to improve the biosynthesis and demulsifying efficiency of the biodemulsifier. The optimal carbon source was liquid paraffin, while waste frying oil could also be an alternative carbon source. The optimal nitrogen sources were ammonium sulfate and yeast extract. To further enhance the biodemulsifier efficiency, the optimal cultivation conditions were determined using response surface methodology (RSM) based on central composite rotation design (CCRD). Using the optimized cultivation conditions, the demulsifying ratios increased to 98.23 and 97.65 % for the W/O and O/W model emulsions, respectively. 相似文献
474.
475.
围填海控制线是在工程可行的前提下,不显著改变区域海洋动力格局和岸滩演变趋势的最大围填外包络线,能够最大限度地协调围填海与海洋资源环境保护之间的关系。以苏北浅滩腰沙为例,在对围填海控制性因素进行筛选、识别与分析的基础上,根据各控制性因素的控制要求,设计了围填海控制性指标。应用潮流数值模拟和泥沙回淤预测技术,采用分层次筛选和迭代逼近的方法,构建围填海控制线迭代优选模型,分析不同围填海方案对海洋动力格局演变的影响,计算得到腰沙的围填海控制线为理论基面+28 m。提出的研究方法和迭代优选模型可为沿海省市围填海控制线的制定提供参考和方法借鉴,为制定围填海规模总量控制指标提供科学依据 相似文献
476.
在以焦炭为填料的生物滴滤塔对挥发性脂肪酸臭气的处理研究中考察了空床停留时间、臭气浓度、体积负荷以及进气温度等参数对净化效果的影响。结果表明,空床停留时间较长时对臭气降解有利。在停留时间超过97 s时,能实现完全降解;此外,净化率随臭气浓度和体积负荷的不断增加呈先增加后降低的趋势。当臭气浓度为24.29 mg/m3即臭气的体积负荷为3 g/(m3·h)时,去除率约为96%;当臭气浓度增至1 345.74 mg/m3即体积负荷增至18 g/(m3·h),去除率达100%;然而,当臭气浓度增至4 934.38 mg/m3即体积负荷增至66 g/(m3·h)时,去除率降至73.1%。另外,进气温度对净化率也有一定程度影响。当进气温度较低时,净化效率相对较高。 相似文献
477.
478.
Ming-Hong Wu Liang Tang Gang Xu Jing Ma Ning Liu Liang Wang Jian-Qiu Lei 《Environmental science and pollution research international》2013,20(4):2651-2660
Fourteen and 17 sediment samples were collected from three main rivers of Shanghai in July and November, respectively. Eight polybrominated diphenyl ether (PBDE) congeners (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, and BDE-209) were detected in these samples to clarify the pollution status in the metropolis. Instrumental analyses showed that the concentrations of ∑8PBDEs ranged from 10.97 to 64.05 ng/g dry weight (dw), with an average value of 29.71 ng/g dw. BDE-209 was the predominant congener accounting for more than 97 % of total PBDEs, followed by BDE-47 and BDE-99. Remarkable spatial and seasonal distributions of PBDE concentrations were observed, suggesting that local sources, seasonal climates, and hydrologic conditions might be the influencing factors. Moderate correlations (r 2?=?0.28–0.51, p?<?0.05) were found between total organic carbon and PBDEs, which indicated that organic carbon content influenced the distributions of PBDEs in sediment of Shanghai at some extent. Hazard quotients revealed PBDEs posed no potential risk to benthic organisms in the study area at present. 相似文献
479.
Wen-Xiu Liu Wei He Ning Qin Xiang-Zhen Kong Qi-Shuang He Hui-Ling Ouyang Fu-Liu Xu 《Environmental science and pollution research international》2013,20(4):2033-2045
The levels of organochlorine pesticides (OCPs) in the water, suspended solids, and sediments from Lake Chaohu during the high water level period were measured by a solid-phase extraction gas chromatograph–electron capture detector. The spatial distributions of the three phases and the water/suspended solids and sediment/water partition coefficients were analyzed. The results showed the following: (1) The mean contents of OCPs in the water, suspended solids, and sediments were 132.4?±?432.1 ng/L, 188.1?±?286.7 ng/g dry weight (dw), and 13.7?±?9.8 ng/g dw, respectively. The dominant OCP components were isodrin (85.1 %) for the water, DDTs (64.4 %) for the suspended solids, and both isodrin (48.5 %) and DDTs (31.8 %) for the sediments. (2) β-HCH was the primary isomer of HCHs in the water and sediments, and the proportions were 61.7 and 41.3 %; γ-HCH was the primary isomer in the suspended solids, accounting for 49.3 %; p,p′-DDT was the dominant content of DDTs in the water and suspended solids, whereas p,p′-DDD was the main metabolite of DDTs in the sediments. (3) The concentrations of contaminants in the water from the western lake were greater than those from the eastern lake, but the concentrations in the suspended solids from the western lake were less than those from the eastern lake. (4) There was no significant correlation between the water–suspended solids partition coefficient K d and the n-octanol–water partition coefficient K ow, and between the sediment–water organic-C weighted sorption coefficients K oc and K ow. 相似文献
480.