Direct electrochemistry of glucose oxidase and biosensing for glucose based on DNA/chitosan film

Glucose oxidase (GOD) is widely used in the glucose biosensor industry. The amperometric biosensors based on directly electron transfer (DET) between an electrode and immobilized GOD are especially promising. In this article, GOD was immobilized with a DNA/chitosan bio-material film on GC electrode, and the DET of GOD on DNA/chitosan was studied. The cyclic voltammetric results indicated that the GOD immobilized in the DNA/chitosan film underwent DET reaction, and the cyclic voltammogram displayed a pair of well-defined redox peaks with a formal potential of ?0.45 V (vs. Ag/AgCl) at pH 5.5. The response showed a surface-controlled electrode process with an electron transfer rate constant of 0.91 sec^?1 determined in the scan rate range from 10 to 100 mV/sec. The GOD immobilized in DNA/chitosan membrane retained its biocatalytic activity and stability. The immobilized GOD could electrocatalyze the reduction of dissolved oxygen and resulted in a great increase of the reduction peak current. Upon the addition of glucose, the reduction peak current decreased, which could be used for glucose detection with a sensitivity of 0.48 μA/(mmol/L), a linear range from 0.04 to 2.28 mmol/L and a detection limit of 0.04 mmol/L at a signal-to-noise ratio of 3. The sensor could exclude the interference of commonly coexisted uricacid and ascorbic acid.     

海藻酸钠强化超滤含铜废水

聚合有机物强化超滤技术因具有操作压力低、膜通量大且截留效果好的优点,而受到了广泛的关注.文章研究了天然有机物海藻酸钠强化超滤去除模拟含铜废水的特性及影响因素,试验结果表明,当海藻酸钠投加量为100 mg/L.pH=6.0,温度为25℃,Cu2+初始浓度为10mg/L时,MWCO(截留分子量)为4 kDa.6 kDa,1...     

环境友好季铵盐杀菌剂的合成与抗菌特性

为了在提高季铵盐的杀菌活性的同时消除其在使用过程中对环境的二次污染,合成了一种可生物降解的新型双子季铵盐杀菌剂,1,5-(戊撑)双(N,N`-乙酸十二酯溴化铵)[略作:PDA]。利用二甲基甘氨酸和月桂醇的酯化反应得到了N,N-二甲基甘氨酸酯,再使用1,5-二溴戊烷将其季铵化得到目的物,经1H-NMR检测确认了合成物的结构。以最小抑菌浓度为指标评价了PDA的抗菌特性,并以活性污泥法评价了其生物降解特性。结果表明,与目前最广泛使用的季铵盐杀菌剂苯扎氯铵(BAC)相比较,无论是对于革兰氏阳性菌还是阴性菌PDA都具有更高的杀菌活性,平均MIC为3.11μmol/L。PDA还改善了一般季铵盐的环境稳定性,其抗菌力基本不受环境pH和温度的影响。PDA具有良好的生物降解性,在实验条件下第8天就可以达到100%的降解,相对于具有相似双链结构的季铵盐N,N`-二甲基-N,N`-双十二烷基氯化铵(D1221)提高了一倍。     

二恶英类持久性有机污染物（POPs）现状调查及防治对策

文章通过对包头市2009年二恶英类持久性有机污染物（POPs）的现状调查,分析烧结、炼钢、废弃物焚烧等主要污染源分布和核定污染源排放量,评估主要污染源污染负荷,提出相应的防治对策。     

利用绿色巴夫藻去除海水养殖水体中N、P的条件优化

为了研究常用饵料微藻绿色巴夫藻对高密度海水养殖水体中N、P的去除能力,探索去除养殖水体中N、P的最优条件,选择起始藻细胞数量、养殖水体稀释率、温度、光照和盐度五种因素开展正交试验.结果表明养殖水体稀释率为50%时,绿色巴夫藻对NH4-N和PO4-P的平均去除率最高,分别为98.7%和85.5%.各种因素影响藻体去除水体...     

铜矿尾矿库无土修复植物营养元素含量特征

分析了安徽铜陵冬瓜山铜矿杨山冲尾矿库10种无土修复植物中10种营养元素含量特征。结果表明：平均含量大于1000μg·g^-1的元素有7个,含量从太到小顺序为Ca〉N〉S〉K〉Fe〉Mg〉P;平均含量为100μg·g^-1～1000μg·g^-1。的元素有3个,含量从大到小的顺序为Na〉Si〉Mn。营养元素含量的变异系数...     

粉煤灰对含铬废水的吸附研究

通过静态吸附实验,研究原状粉煤灰与粉煤灰滤料对Cr(Ⅵ)的吸附效果的影响,并通过正交实验进行实验结果对比。实验确定粉煤灰滤料的吸附平衡时间为90 min,在pH为3的条件下适于进行吸附实验;同时,粉煤灰滤料的吸附性能优于原状粉煤灰,六价铬溶液的初始浓度、滤料的投加量以及温度的改变对吸附性能具有显著影响,且粉煤灰滤料吸附时所受影响更为明显。     

铁碳微电解降解高浓度制药废水

采用铁碳微电解法对高浓度制药废水进行降解实验研究,考察了铁碳微电解反应时间、铁碳体积比、进水pH值、固液比等因素对降解效果的影响。结果表明,铁碳微电解反应时间为100 min,铁碳体积比为1:1,进水pH值为4.0,固液比为15%时,CODcr去除率接近60%,色度去除率超过80%,BOD5/CODcr也由原水的不足0.10上升到0.43,可生化性得到提高。同时也考察了铁屑活化对降解效果的影响。     

城市园林绿化资源及调查技术研究

城市园林绿化资源是主要服务于城市居民、支持植物和以植物为主体的城市生态系统存在与发展的因素和条件,及其各种天然的和经过人工改造的结果,具有明显的自然属性和社会属性两重性。城市园林绿化资源调查就是全面查清城市园林绿化资源的自然属性和社会属性．状态。研究了调查因子的设计,调查技术规程的架构,调查图斑的概念和区划方法,及绿色遥感信息提取和资源管理地理信息系统开发技术设计,并应用于2010开展的徐州市城市园林绿化资源调查中,取得了较好的成果。     

Preliminary study of groundwater denitrification using a composite membrane bioreactor

A composite membrane bioreactor (CMBR) integrating the immobilized cell technique and the membrane separation technology was developed for groundwater denitrification. The CMBR had two well mixed compartments with one filled with the nitrate-containing influent and the other with a dilute ethanol solution; the compartments were separated by the composite membrane consisting of a microporous membrane facing the influent and an immobilized cell membrane facing the ethanol solution. Nitrate and ethanol molecules diffused from the respective compartments into the immobilized cell membrane where nitrate was reduced to gaseous nitrogen by the denitrifying bacteria present there with ethanol as the carbon source. The microporous membrane was attached to one side of the immobilized cell membrane for retention of the disaggregated bacteria. Relative to the single dose of external ethanol, the two-dose supplementation produced better treatment results as evidenced by the lower concentrations of NO₃⁻-N and ethanol (as measured by total organic carbon) of the effluent. The batch treatment in CMBR removed most of the nitrate in the influent and attained a stable denitrification rate of 0.1 g·m⁻²·h⁻¹ for most of the 96-h cycles during the 30-cycle study. The effluent was essentially free of ethanol and nitrite nitrogen.