浅谈BOD_5的质量控制

接种稀释水是做好ＢＯＤ５质量控制的关键,根据不同的季节、不同的温度、不同深度的花园土,以得到较理想的接种稀释水。     

高藻含量水体中BOD_5监测方法探讨

分析了高藻含量水体中BOD5偏高产生的主要原因,是由于藻类光合作用使水中溶解氧大幅增高引起的.并进一步通过实验,验证了对于高藻含量水体中BOD5的监测,采用硫酸铝絮凝沉淀、离心分离后测定,可消除藻类干扰的有效性.     

新形式下工业废水BOD_5稀释倍数的计算

推导了 BOD5稀释系数的量值关系 ,得出 BOD5稀释系数与样品的可生化性成正比 ,与稀释后水样的耗氧量成反比 ,并据此进一步分析了如何对样品的可生化性和稀释后水样的耗氧量进行预期。在此基础上从实际出发 ,根据工作经验简化和优化了稀释倍数的计算 ,达到提高测定准确度 ,降低劳动强度的目的     

高晶度Mn-Fe LDH催化剂活化过一硫酸盐降解偶氮染料RBK5

采用改进的共沉淀结合水热法制备高晶度锰铁层状双金属氢氧化物作为催化剂,用于高效活化过一硫酸盐(PMS)降解活性黑5(RBK5).通过X射线粉末衍射仪(XRD)、扫描电子显微镜(SEM)、X射线能谱分析(EDS)、傅里叶变换红外光谱仪(FTIR)以及X射线光电子能谱(XPS)对材料进行表征,证明成功合成了结晶度高、层状结构突出的Mn-Fe LDH.同时探究了锰铁量比,催化剂投加量,PMS浓度和初始pH值等因素对RBK5的吸附效果、催化降解及反应动力学的影响.结果表明,高晶度Mn-Fe LDH催化剂具有良好的吸附能力和高效的催化效率,在n(Mn)/n(Fe)比为1∶1,催化剂投加量为0.2 g·L^-1,PMS浓度为1 mmol·L^-1,初始pH为7时,RBK5(20 mg·L^-1)在90 min内降解率可达86%,整个反应过程符合拟一级动力学(R²>0.9).自由基猝灭实验表明,Mn-Fe LDH/PMS体系降解RBK5为SO^-₄·和·OH两种活性自由基...     

BOD_5测试方法的改进

根据多年污水常规监测及实验室内质控样的分析,得出经验常数,引用前人推导的公式,对确定BOD5测定过程中稀释倍数的常规方法进行了改进,以达到降低工作强度,提高监测人员工作效率的目的。     

Wet air oxidation treatment of H acid wastewater

１ＩｎｔｒｏｄｕｃｔｉｏｎＨａｃｉｄｍｏｎｏｓｏｄｉｕｍｓａｌｔ（４ａｍｉｎｏ５ｈｙｄｒｏｘｙ２，７Ｎａｐｈｔｈａｌｅｎｅｄｉｓｃｕｌｆｏｎｉｃａｃｉｄｍｏｎｏｓｏｄｉｕｍｓａｌｔ，ｈｅｒｅｉｎａｆｔｅｒｒｅｆｅｒｅｅｄｔｏａｓ“Ｈａ...     

Differences of cadmium absorption and accumulation in selected vegetable crops

ＩｎｔｒｏｄｕｃｔｉｏｎＣａｄｍｉｕｍｉｓｐｒｉｎｃｉｐａｌｌｙｄｉｓｐｅｒｓｅｄｉｎｎａｔｕｒａｌａｎｄａｇｒｉｃｕｌｔｕｒａｌｅｎｖｉｒｏｎｍｅｎｔｓｔｈｒｏｕｇｈｖａｒｉｏｕｓａｇｒｉｃｕｌｔｕｒａｌ,ｍｉｎｉｎｇａｎｄｉｎｄｕｓｔｒｉａｌａｃｔｉｖｉｔｉｅｓａｓｗｅｌｌａｓｒｅｓｕｌｔｉｎｇｆｒｏｍｔｈｅｅｘｈａｕｓｔｇａｓｅｓｏｆａｕｔｏｍｏｂｉｌｅｓ(Ｄａｓ,1 997) .Ｔｈｉｓｔｒａｃｅｍｅｔａｌｉｓｔｈｅｐｏｌｌｕｔａｎｔａｎｄｐｏｔｅｎｔｉａｌｔｏｘｉｎｔｈａｔｈａｓｕｎｋｎｏｗｎｆ…     

A pitfall in the prenatal diagnosis of Lesch-Nyhan syndrome by chorionic villus sampling

The ratio of the activities of catabolic enzymes such as 5′-nucleotidase and purine nucleoside phosphorylase to that of hypoxanthine-guanine phosphoribosyltransferase (HPRT) may be much higher in frozen or cultured chorionic villus cells than in cultured amniotic fluid cells, cultured fibroblasts, or red blood cells. Consequently, unless these catabolic activities are controlled the observed activity of HPRT may be greatly decreased, and a false diagnosis of Lesch-Nyhan syndrome may result. For a reliable diagnosis, the reaction products of HPRT must be protected from catabolism.     

(艹屈)和5-甲基(艹屈)的ab initio计算

湾区非角环上的甲基取代能大大增加多环芳烃的致癌性,量子化学的从头计算(ab initio)指出,5-甲基(艹屈)C1-C2键的电子性质有利于在此健发生亲电反应,电子密度分布图说明5-甲基(艹屈)在C1—C2键周围的电子密度明显大于(艹屈)相应部分的电子密度,这也有利于亲电试剂的进攻,因而在代谢过程中,5-甲基(艹屈)容易在此位置发生亲电氧化形成环氧化物,进而形成终致癌剂,这就使5-甲基(艹屈)的致癌性比(艹屈)大大增强。     

Synthesis and environmental degradation of polyesters based on poly (ε-caprolactone)

Poly (-caprolactone) (PCL), poly (-valerolactone) (PVL), poly (-caprolactone-co--valerolactone) [P(CL-co-VL)], and poly (-caprolactone-co-ethylene oxide-co--caprolactone) (PCL-PEO-PCL) were synthesized by ring-opening and diol-initiated polymerization of -caprolactone and -valerolactone. The degradation of the samples by chemical hydrolysis and in a soil burial test was evaluated. It was found that PCL, PVL, and P(CL-co-VL) degrade mainly enzymatically. The rate of degradation depends on their molecular weight, chemical structure, composition, and morphology. PCL-PEO-PCL block copolymers exhibit a repelling effect to the microorganisms in the soil, which depends on the molecular weight and relative amount of PEO block in the copolymer.