Reactive oxygen species metabolism during the cadmium hyperaccumulation of a new hyperaccumulator Sedum alfredii （Crassulaceae）

Sedum alfredii Hance, a newly discovered hyperaccumulator, could serve as a good material for phytoremediation Cd polluted sites. Malondialdehyde (MDA), reactive oxygen species (ROS) and antioxidases (catalase (CAT); superoxide dismutase (SOD); peroxidase (POD)) in the leaf were determined when S. alfredii was treated for 15 d with various CdCl2 concentrations ranging from 0 to 800 μmol/L. The results showed that the production rate of 2′,7′-dichlorofluorescein (DCF), which is an indicator of ROS level, reached up to the maximum at 400 μmol/L CdCl2 and then declined with the increase of CdCl2 concentration, while MDA accumulation tended to increase. CAT activity was significantly inhibited at all tested CdCl2 concentrations and SOD activity was sharply suppressed at 800 μmol/L CdCl2. However, the enhancement of POD activity was observed when CdCl2 concentration was higher than 400 μmol/L. In addition, its activity increased when treated with 600 μmol/L CdCl2 for more than 5 d. When sodium benzoate, a free radical scavenger, was added, S. alfredii was a little more sensitive to Cd toxicity than that exposed to Cd alone, and the Cd accumulation tended to decline with the increase of sodium benzoate concentration. It came to the conclusions that POD played an important role during Cd hyperaccumulation, and the accumulation of ROS induced by Cd treatment might be involved in Cd hyperaccumulation.     

采用氢氧化钠溶液循环浸出法脱除高砷阳极泥中的砷

采用氢氧化钠溶液循环浸出法处理高砷阳极泥（简称阳极泥）,考察了氢氧化钠溶液与阳极泥质量比（简称液固比）等因素对限极泥中砷、锑、铅浸出率的影响。在液固比为5、氢氧化钠浓度为2．0moL／L、反应温度为70～85℃、反应时间为8h的条件下,砷浸出率可达95％以上;含砷浸出液经硫化钠沉砷后可返回浸出工序重复使用,在硫化钠与砷质量比大于3时,浸出液沉砷率维持在80％以上,同时回用浸出工序后,砷浸出率达95％以上,且铅、锑流失率较低。     

铬酸钠晶体中铝酸钠杂质的分离

重点研究了含有杂质氢氧化钠和铝酸钠的酸钠晶体中铬酸钠和铝酸钠溶解动力学,洗涤一定组成的混合晶体的结果表明,两者在溶解动学方面具有很大差别,铬酸钠能迅速达到溶解平衡,而铝酸钠极易形成过程饱和溶液,且有一定的稳定性。     

加铂修饰型催化剂光催化氧化五氯酚

研究了负载型催化剂加铂修饰,并探讨了铂在催化剂中的含量对其催化活性的影响。通过光催化降解五氯苯酚钠实验,结合催化剂晶型结构和比表面分析,评价所制备的催化剂。实验结果表明：加铂修饰型催化剂的催化活性明显高于未修饰催化剂的活性。当铂在催化剂中的重量百分比为1．4％－1．6％时其光催化活性最高。     

松针资源开发利用-绿色素制备

本研究以松针为原料,经过一系列物理、化学过程制得天然含锌绿色素--叶绿素锌钠,测定了叶绿素锌钠盐的质量指标、吸光度、耐热性、耐光性,并对叶绿素和叶绿素锌钠的稳定性进行了比较研究.     

Ag~+在含Cl~-培养基中的毒性初探

纳米银(Ag NPs)和硝酸银(AgNO_3)的毒性研究已成为环境科学的焦点问题之一。毒性测试时LB培养基中的Cl~-势必会对Ag~+的毒性产生影响。为了探究Cl~-对Ag~+的溶解态及毒性的影响,计算了常温(25℃)和试验条件(37℃)下含1%NaCl的LB培养基中Ag Cl1-xx各组分的生成量及在体系中所占比例,测定了不同NaCl质量分数的LB培养基中AgNO_3对革兰氏阳性菌(B.subtilis)和阴性菌(E.coli)的毒性。结果表明,AgNO_3在含NaCl体系中溶解态银主要为Ag Cl1-xx,而Ag~+未达到有毒的浓度,且随NaCl质量分数增加,AgNO_3的毒性不断增大。因此认为毒性试验中实际发挥毒性作用的是Ag Cl1-xx,尤其是Ag Cl~-2。     

Calcium alginate accelerates elimination of environmental lead in preschool children

Environmental lead poses a serious threat for public health, particularly, for children. The use of substances with metal-binding properties, such as natural alginates, may be a potentially effective method for elimination of toxic metal ions from human body. In present study, effect of calcium alginate isolated from brown algae on distribution of the lead ions in preschool children was investigated. In the beginning of the study, lead concentration in urine, feces, and hair was determined. Then these children were administered a dietary supplement containing calcium alginate for four weeks. The results showed that all children participated in the study had a high baseline median lead level in urine (1.1 µg/L), feces (4.6 µg/g), and hair (5.0 µg/g). Administration of calcium alginate resulted in twofold increase of the urine lead level within two weeks from the start of the treatment. At the end of alginate administration, significant decrease of lead concentration in hair was registered. These results suggest that calcium alginate can potentially prevent accumulation of the lead ions in the body and may be used as an active agent for elimination of this toxic metal from human body.     

阴离子表面活性剂改性水滑石吸附硝基苯的特性研究

以阴离子表面活性剂十二烷基硫酸钠(sodium dodecyl sulfate,SDS)为改性剂,采用共沉淀法在不同表面活性剂浓度,0.5～2.0理论阴离子交换容量(theoretical anion exchange capacity,TAEC)条件下制备了有机水滑石LDH-DS,并用XRD、FT-IR表征了样品的结构特征.结果表明十二烷基硫酸根成功插层进入LDH层间,d003底面间距由0.80 nm增大至3.98 nm.同时研究了LDH-DS对硝基苯的吸附性能,表明有机水滑石对硝基苯的等温吸附曲线符合线型方程(R2>0.99),吸附过程主要为分配作用.随着样品中SDS负载量的增加,LDH-DS对硝基苯的吸附系数Kd相应增强,但有机碳标化的吸附系数Koc值基本保持恒定.吸附热力学实验显示吸附过程为吸热反应,熵增大是吸附过程的驱动力.     

次氯酸钠吸收磷化氢尾气的实验研究

为处理次磷酸钠生产过程中产生的磷化氢尾气,利用次氯酸钠氧化性对其进行吸收,将其转化为次磷酸钠,提高磷资源的回收利用率,降低对环境空气的影响。通过实验研究,分析影响其吸收效果的因子,重点研究了有效氯浓度和pH值对吸收效果的影响。实验结果表明：当载气流速为20ml／min,吸收温度为室温（20℃左右）时,以pH=9,浓度分别为0．75％、7％的次氯酸钠溶液作为一、二级吸收管的吸收液,吸收效果较好,次磷酸钠得率较高。     

Effect of an eco-friendly o/w emulsion stabilized with amphiphilic sodium alginate derivatives on lambda-cyhalothrin adsorption–desorption on natural soil minerals

The effects of amphiphilic O/W emulsions,stabilized by the alkyl polyglycoside(APG)or cholesterol-grafted sodium alginate(CSAD)/APG systems,on lambda-cyhalothrin adsorption/desorption mechanisms on natural soil minerals(i.e.,illite and kaolinite)were investigated.Sorption and desorption of lambda-cyhalothrin onto soil minerals was studied via batch equilibration to give insight into the adsorption equilibrium,kinetics,and thermodynamics of lambda-cyhalothrin adsorption onto minerals.The results indicate the following:(i)The adsorption processes for the APG system and CSAD/APG system include:rapid adsorption,slow adsorption,and adsorption equilibrium.The adsorption kinetics of pesticide on illite and kaolinite are in accordance with the Ho and McKay model,and the adsorption isotherm conforms to the Freundlich model.In addition,the adsorption processes of pesticide for the two systems on minerals were spontaneous and feasible(ΔG~00),endothermic(ΔH~00),and mainly involved chemical bonding(ΔH~060).(ii)The equilibrium adsorption percentages of the pesticide on illite for the APG system and CSAD/APG system were 42.4%and 64.8%,and the corresponding equilibrium adsorption percentages on kaolinite were 40.8%and 61.8%,respectively.Moreover,the pesticide adsorption rate K_(2-CSAD/APG)was faster than K_(2-APG),and its adsorption capacity K_(f-CSAD/APG )was greater than K_(f-APG).Meanwhile,the pesticide desorption K_(fd)in the CSAD/APG system was smaller than that in the APG system.As a result,this eco-friendly O/W emulsion based on amphiphilic sodium alginate derivatives might provide a green pesticide formulation,since it could reduce the amount of lambda-cyhalothrin entering aquatic systems to threaten non-target fish and invertebrate species.