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771.
碳酸氢铵溶液解吸二氧化碳研究 总被引:4,自引:1,他引:4
对氨法脱碳主要吸收产物碳酸氢铵溶液受热解吸CO2的过程开展实验研究,借以了解吸收剂再生特点.同时,考虑到常温下碳酸氢铵溶解度和不相称溶解的限制,选择对2mol·L-1以下浓度溶液进行60~90℃常压加热,考察加热温度及溶液浓度对CO2解吸过程的影响.结果表明,在实验条件下,碳酸氢铵溶液解吸CO2的选择性强,解吸比例随加热温度的升高和溶液浓度的增大而上升,但低于50%.反应动力学分析结果表明,碳酸氢铵溶液热分解过程为二级不可逆反应,反应速率常数k=4.4×1013exp(-13541/T). 相似文献
772.
嗜碱细菌复合碳源条件下对麦草木质素的降解 总被引:18,自引:0,他引:18
在碱性液体培养条件下(pH≈10.5), 研究复合碳源共代谢最佳综合条件下嗜碱性木质素降解细菌6号菌株产酶、降解能力及菌株的生长状况.结果显示,虫漆酶(Laccase)在培养的第4天酶活达到最高值2915.37U/L、锰依赖过氧化物酶(MnP)在培养的第8天酶活达到最高值1152.88U/L,培养10d麦草中木质素降解49.84%.同时通过扫描电镜分析探讨了6号菌株降解木质素的微观过程,证明了6号菌株优先降解木质素的特性和降解方式. 相似文献
773.
Sulfonamides are used in human therapy, animal husbandry and agriculture but are not easily biodegradable, and are often detected in surface water. Sulfamethazine (SMZ) and sulfadiazine (SDZ) are two widely used sulfonamide antibiotics that are used heavily in agriculture. In this study, they were degraded in an aqueous system by chlorination after pre-oxidation with ferrate(VI) (FeVIO42 ?, Fe(VI)), an environmentally friendly oxidation technique that has been shown to be effective in degrading various organics. The kinetics of the degradation were determined as a function of Fe(VI) (0–1.5 mg/L), free chlorine (0–1.8 mg/L) and temperature (15–35°C). According to the experimental results, SMZ chlorination followed second-order kinetics with increasing Fe(VI) dosage, and the effect of the initial free chlorine concentration on the reaction kinetics with pre-oxidation by Fe(VI) fitted a pseudo-first order model. The rate constants of SDZ and SMZ chlorination at different temperatures were related to the Arrhenius equation. Fe(VI) could reduce the levels of THMs formed and the toxicity of the sulfonamide degradation systems with Fe(VI) doses of 0.5–1.5 mg/L, which provides a reference for ensuring water quality in drinking water systems. 相似文献
774.
775.
Environmental pollution by persistent toxic substances and health risk in an
industrial area of China 总被引:1,自引:0,他引:1
Jing Li Yonglong Lu Yajuan Shi Tieyu Wang Guang Wang Wei Luo Wentao Jiao Chunli Chen Feng Yan 《环境科学学报(英文版)》2011,23(8):1359-1367
Soil is an important environmental medium that is closely associated with humans and their health. Despite this, very few studies
have measured toxicants in soils, and associated them with health risks in humans. An assessment of health effects from exposure to
contaminants in soils surrounding industrial areas of chemical production and storage is important. This article aims at determining
pollution characteristics of persistent toxic substances (PTS) in an industrial area in China to unravel the relationship between soil
pollution by PTS and human health. One hundred and five soil samples were collected and 742 questionnaires were handed out to
residents living in and around an industrial area around Bohai Bay, Tianjin in Northern China. Concentrations of organochlorine
pesticides and polycyclic aromatic hydrocarbons (PAHs) were determined in soil. Mann-Whitney U and binary multivariate nonconditional
logistic regression models were employed to analyze the relationship between health indicators of local residents and
contaminant levels. Odds ratio (OR) and a 95% confidence interval (CI) for health incidences were also calculated. The average
concentrations of DDT (73.9 ng/g), HCH (654 ng/g) and PAHs (1225 ng/g) were relatively high in the industrial area. Residents living
in the chemical industry parks were exposed to a higher levels of PTS than those living outside the chemical industry parks. This
exposure was associated with a higher risk of breast cancer (OR 1.87, 95% CI 0.12–30.06), stomach cancer (OR 1.87, 95% CI 0.26–
13.41), dermatitis (OR 1.72, 95% CI 1.05–2.80), gastroenteritis (OR 1.59, 95% CI 0.94–2.68), and pneumonia (OR 1.05, 95% CI
0.58–1.89). 相似文献
776.
CANON工艺处理猪场沼液的启动及微生物种群结构分析 总被引:3,自引:0,他引:3
在连续流合建式反应器内接种普通活性污泥,以实际猪场沼液作为进水,保持温度为(30±1)℃,控制低溶解氧(DO浓度为(0.5±0.1)mg·L~(-1)),通过分阶段提高氨氮浓度的方式启动CANON(Completely autotrophic nitrogen removal over nitrite)工艺,同时采用高通量测序技术对反应器启动前后的微生物种群结构进行分析.结果表明,反应器可在210 d实现成功启动CANON工艺,启动成功后,当猪场沼液进水氨氮浓度为450 mg·L~(-1)时,氨氮和总氮的去除率分别达到69.8%和61.1%;出水(NO_3~--N+NO_2~--N)/ΔNH_4~+接近0.11.同时,CANON工艺启动成功后,微生物种群结构发生了很大的变化:其优势菌门为变形菌门(Proteobacteria)(36.16%)、绿弯菌门(Chloroflexi)(14.22%)、浮霉菌门(Planctomycetes)(11.07%)、酸杆菌门(Acidobacteria)(10.41%)和绿菌门(Chlorobi)(12.82%);与脱氮功能相关的菌属为Candidatus_Brocadia (ANAMMOX菌)、Nitrosomonas(AOB菌)、Comamonadaceae(反硝化菌)和Xanthomonadaceae(反硝化菌)等. 相似文献
777.
778.
通过应用"清洁生产审核"方法,对小型废钢电炉除尘系统改造方案进行全面深入的分析和方案筛选,充分利用已有的系统和设备,并通过以屋顶代罩的合理改进、提高集气效率;以最小的投入、达到有效控制污染的目的。 相似文献
779.
分级燃烧中固体吸附剂对痕量金属排放的影响 总被引:8,自引:1,他引:8
在一维煤粉燃烧炉上进行了烟煤添加不同吸附剂的分级燃烧试验.试验过程中保持总的空气过剩系数a为1.20,分级风量占总风量的20%,炉内温度为1100℃左右.试验发现分级燃烧会增加亚微米颗粒排放,不利于对痕量重金属元素的控制,尤其对挥发性大的元素(如Cu和Ni)影响越明显.热力学计算也表明不同气氛下痕量元素的形态变化过程有很大差异,还原气氛下痕量元素会生成不稳定的次氧化物和还原性产物.固体吸附剂对煤中重金属的排放具有吸附作用,并且不同的吸附剂对不同的痕量元素的吸附效果各不相同,不分级时,对Co,Cr,Ni元素来说,高岭土的吸附效果最好;对Be元素,灰质白云石效果最好;CaO则对Cu元素的吸附效果最好.而在分级情况下,对元素Be,Cr,Ni,灰质白云石的效果最好;对Co和Cu,高岭土的吸附最好. 相似文献
780.