Preparing graphene from anode graphite of spent lithium-ion batteries

With extensive use of lithium ion batteries (LIBs), amounts of LIBs were discarded, giving rise to growth of resources demand and environmental risk. In view of wide usage of natural graphite and the high content (12%–21%) of anode graphite in spent LIBs, recycling anode graphite from spent LIBs cannot only alleviate the shortage of natural graphite, but also promote the sustainable development of related industries. After calcined at 600°C for 1 h to remove organic substances, anode graphite was used to prepare graphene by oxidation-reduction method. Effect of pH and N₂H₄·H₂O amount on reduction of graphite oxide were probed. Structure of graphite, graphite oxide and graphene were characterized by XRD, Raman and FTIR. Graphite oxide could be completely reduced to graphene at pH 11 and 0.25 mL N₂H₄·H₂O. Due to the presence of some oxygen-containing groups and structure defects in anode graphite, concentrated H₂SO₄ and KMnO₄ consumptions were 40% and around 28.6% less than graphene preparation from natural graphite, respectively.

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碳羟磷灰石的制备及其对水中Cu2+的吸附

以废弃蛋壳为原料、尿素为添加剂,采用掺杂技术制备碳羟磷灰石（CHAP）,并用其作吸附剂去除水中的Cu^2＋。考察了Cu^2＋的初始质量浓度、pH、吸附时间、CHAP加入量及温度等因素对CHAP吸附Cu^2＋效果的影响。实验结果表明,在温度40℃、溶液pH6、搅拌1h后静置1h的条件下,用5g／L的CHAP处理Cu^2＋初始质量浓度为60mg／L的水溶液,Cu^2＋去除率为99．30％。吸附等温线基本符合Freundlich和Langmuir方程。     

On the intensity and type transition of land use at the basin scale using RS/GIS: a case study of the Hanjiang River Basin

The purpose of this study is to investigate the land use intensity and land use change type at the basin scale in the middle and lower reaches of the Hanjiang River Basin (in Hubei Province, China) by combining the Landsat TM images in 1995 and 2000 with the land use database (in scale 1:10,000) and relative data. In this study, the basic data is acquired from the interpretation of remote sensing (RS) images. The intensity of land use and the rate of change in double-directions of land use dynamics are calculated with the support of software ARC/INFO. The intensity of land use is indicated by the intensity coefficient of land use, and the transition of land use types is quantified as the rate of change in double-direction of land use types and also expressed as the transition matrix of land use types. The results are expressed in space by Geographic Information System (GIS) software. Results of this study show that (1) the intensity of land use is high in the study region, the intensity coefficients of land use in 1995 and 2000 are 260.025 and 290.526, respectively, and the intensity of development and utilization of land is trend to increscent; and (2) the rate of land use change in double directions in the whole study region is 0.52 with great spatial variation and the differentiation of land use types. In the differentiation of land use types, the unutilized land (with the rate to 4.391) is developed fast, the grassland (with 2.836) and water area (with 1.664) are disturbed severely, and these changes will influence the eco-environment in the Hanjiang River Basin and all the Yangtze Basin. The rates of the farmland and the woodland are 0.424 and 0.344, respectively, meaning that the fundamentals of regional human-environmental system are relative stable. With this study, we can conclude that (1) the patterns of land use are increasingly changing in the study region, the environmental impacts are escalated on this stage, and the further outcomes are destined to change the stability of the regional human–environmental system; and (2) the most useful method to study the present land use and its change is through the use of the RS/GIS with the land use database (in scale 1:10,000).     

不同供氧策略对SBBR反应器实现短程硝化厌氧氨氧化的影响分析

以氨氮浓度较高的垃圾渗滤液为处理对象,分析研究了不同供氧策略对SBBR反应器实现短程硝化厌氧氨氧化的影响.在4种不同供氧策略(a、b、c和d的总供氧时间分别为16h、12h、12h和8h;好氧/厌氧交替频率分另U为4h/2h、3h/3h、2h/2h和2h/4h)下同步启动反应器,保持各反应器内环境温度为(30.0±4-0.5)℃,并控制曝气阶段溶解氧(DO)浓度为(1.2±0.1)mg·L-1.实验结果表明,反应器内的微生物经过124d的驯化和增殖,具有一定的脱氮能力,但是效果不同,其中,采用总供氧时问为12h,好厌氧交替频率为2h/2h供氧策略的反应器c效果最好,氨氮去除率达到96.6%左右,而且抗氨氮冲击负荷的能力最强,最大的氨氮容积负荷为0.186 g·(L·d)-1;在曝气阶段由于DO浓度的限制,亚硝酸盐出现积累;缺氧阶段,由于厌氧氨氧化细菌和反硝化细菌的协同作用,亚硝酸盐氮和氨氮同时被去除,且没有硝酸盐的积累.从4个反应器和渗滤液原水中提取细菌总DNA,通过PCR-DGGE技术获得DGGE图谱.分析图谱中各泳道的条带数目和条带亮度、各泳道间的相似性系数C,值,结果表明,不同供氧策略对反应器内的细菌多样性和种群结构产生了较大影响.     

基于腐蚀与盐堵塞问题的超临界水氧化研究进展

超临界水氧化(简称SCWO)以其特有的优点成为了引人注目的有机废水处理方法.在操作过程中,有机物与氧化剂呈现为快速的均相反应,在数分钟内便可完全氧化生成CO2和H20.尽管已建造了工业规模的SCWO装置并用于处理化学废水,但该技术所存在的设备腐蚀以及设备因盐沉积而堵塞的问题制约着该技术的推广应用.为解决上述问题,科技工作者对SCWO工艺进行了改进,并提出了多种新颖的SCWO反应器设计思想.综述了基于解决设备腐蚀与盐堵塞问题的SCWO研究进展,并对相关问题进行了讨论.     

滴流床反应器中苯酚催化湿式氧化集总反应动力学研究

在自行研制的滴流床反应器中,以苯酚配水溶液作为研究对象,采用负载型CuO/γ-Al2O3作为催化剂,于连续流工况下实验研究了苯酚催化湿式氧化(CWO)过程,建立了滴流床反应器拟均相一维活塞流模型,并结合集总动力学反应模型对实验数据进行拟合.该模型计算值均能较好的预测实验结果;模型引入了集总动力学概念,较深入地解释了催化湿式氧化反应过程.由模型计算所得的动力学参数表明,在所使用的催化剂上苯酚较易氧化为中间产物,但苯酚和中间产物的深度氧化不易进行.     

电-Fenton法预处理青霉素废水的降解规律研究

研究电-Fenton法预处理青霉素钠(penicillin G sodium,PGN)模拟废水的降解规律,分析预处理过程中PGN浓度、COD、TOC的变化情况及BOD5/COD改善情况.当T=20℃、pH=3时,投加0.5g/L FeSO4、0.2 mL/L H2O2,于0.3 A电流下降解浓度为100 mg/L的PGN废水,120 min后PGN去除97.9%,COD去除76.7%,TOC去除59.8%,BOD5/COD由0升至0.4,有效提高了废水的可生化性.以红外光谱(infrared spectrogram,IR)和液相色谱-质谱联用(Liquid chromatogramMass chromatogram,LC-MS)检测青霉素钠的降解产物,说明青霉素钠抑菌的关键结构b-内酰胺环被破坏,抗菌性消失,有助于生物处理有效去除.     

间接竞争ELISA法测定稻田土壤中除草剂毒莠定的残留量

通过对反应体系中酶标二抗(辣根过氧化物酶标记羊抗兔IgG)和抗体的最佳稀释浓度等条件的筛选和确定,最终建立了一种快速灵敏地测定污染稻田土壤中毒莠定残留量的方法--间接竞争ELISA分析方法.结果表明,酶标二抗和抗体的最佳稀释度均为1:500(体积比),毒莠定的检出下限达到5 ng·mL-1,在0.07～0.7μg·mL-1浓度范围内有良好的线性;土壤浸出液加样的平均回收率为104.11%,变异系数在3.13%～11.13%之间,符合农药残留分析的要求;样品基质对检测结果没有干扰.     

城市生活垃圾卫生填埋场工艺设计及存在问题探讨

推广城市生活垃圾卫生填埋技术是迅速提高我国垃圾无害化处理率的有效办法。根据青铜峡市地理、水文等环境条件,以及该市垃圾组成成分的特点,设计了垃圾卫生填埋场的防渗处理系统,渗沥液收集处理系统和废气收集系统,并对设计中发现的问题进行分析,提出相应的建议,以期为类似地区、条件下垃圾卫生填埋场的设计和建设提供借鉴。     

SCX型脱硫除尘器内部气固两相流场数值模拟

采用FLUENT软件对SCX型脱硫除尘器内部气固两相流场进行数值模拟.气相采用Realizable k-ε湍流模型,颗粒相采用离散相模型(DPM),压力-速度耦合算法选择SIMPLE进行计算.分析了装置内z=0截面上气相压力和速度的分布,并对不同粒径颗粒的浓度和运动轨迹进行计算,还在考虑重力及不考虑重力2种情况下分析了...