羧甲基纤维素/有机蒙脱土纳米复合材料对刚果红的吸附与解吸性能

羧甲基纤维素(CMC)/有机蒙脱土(OMMT)纳米复合材料作为吸附剂应用于废水处理,对其结构进行了表征并对吸附时间、染料初始浓度、染料pH对该吸附剂吸附染料刚果红的影响进行了研究,同时探讨了吸附动力学和吸附热力学。结果表明,羧甲基纤维素与有机蒙脱土已经很好地复合,在吸附温度为30℃条件下,当吸附时间为4 h,染料初始浓度为800 mg/L,染料pH=10时吸附剂对染料表现出较好的吸附效果,吸附量可达156.64 mg/g。吸附符合伪二级动力学模型和Langmuir等温式。分别借助振荡器和超声波对吸附饱和的吸附剂进行解吸,研究解吸时间对吸附剂解吸实验的影响,结果表明,超声波条件下的解吸效果(34.45%)好于无超声波条件(15.69%),超声波有助于提高解吸率。     

环境友好型煤尘抑制剂的制备

我国是煤炭消耗大国,每年因煤炭开采、运输等向大气环境中排放大量煤尘颗粒物,对环境质量和人民的健康生活造成严重影响,并造成巨大的经济损失和资源浪费。以秸秆、淀粉、碱为主要原料,开展环境友好型煤尘抑制剂的制备研究。通过响应面法优化并检验各因素及其对抑尘剂黏度和分散度的影响,得到一种性能优良的环境友好型煤尘抑制剂,并测定其抑尘性能。研究结果表明,抑尘剂原料秸秆、淀粉和碱的最佳质量比为10∶6∶0.9;抑尘性能测试表明,本抑尘剂可在5~6级风速下有效抑制煤尘,表干后成膜结壳,无毒无害,具有较高的环境、经济和社会价值。     

包覆型纳米零价铁的制备及其去除水中的活性艳蓝

采用流变相法,以FeSO4.7H2O∶KBH4=1∶2(摩尔比)为固相介质,0.06 g/mL CMC(羧甲基纤维素)水溶液为液相介质,固液比1∶2,反应2 h制备出包覆型纳米零价铁;采用XRD、TEM等手段对合成的纳米零价铁进行表征。探讨不同反应条件对包覆型纳米铁去除活性艳蓝的影响。实验结果表明,初始活性艳蓝(浓度100 mg/L)pH为5,包覆型纳米铁的投加量为6 g/L,反应时间为30 min时,活性艳蓝的去除率可达96%。通过研究机理,其吸附过程符合二级吸附动力学,降解过程符合一级反应动力学。     

圆板型多孔α-Al2O3陶瓷膜支撑体的制备与表征

以α-Al2O3为骨料,羧甲基纤维素作为成孔剂,高岭土、TiO2作为高温粘结剂和烧结助剂,采用干压成型工艺和固态粒子烧结法制备出了圆板型多孔α-Al2O3陶瓷膜支撑体(=50 mm,厚度为2 mm)。研究了成孔剂用量、高温粘结剂和烧结助剂的用量、烧结温度因素对支撑体性能的影响。结果表明,制得的支撑体孔隙率在34%以上,孔径在2.23～6.75μm,耐酸碱度在98%以上,机械强度高。     

改性CMC聚合物吸附酸法地浸废水中的铀

在温度为70～80℃、单体质量浓度为30%～35%、羧甲基纤维素∶丙烯酸(质量比)为10∶2.5、反应时间为3.5～4 h条件下对CMC进行改性,接枝率可达68%以上。以改性前后的CMC为吸附剂,对模拟酸法地浸含铀废水进行了对比吸附实验研究。结果表明:改性CMC对铀吸附效果最佳的实验条件为:改性CMC质量浓度为0.10 g/L,温度为25℃,pH为5.0,吸附时间100 min,此时铀去除率达到了97.1%,比CMC改性后对铀的吸附率平均提高了近21%。影响吸附效果程度由强到弱的顺序为:改性CMC投加量、pH、吸附时间、温度。     

半-IPN羧甲基纤维素/聚(丙烯酰胺-共-甲基丙烯酸钠)水凝胶制备及其吸附性能

羧甲基纤维素(CMC)水溶液中,通过自由基共聚制备半-互穿网络(IPN)羧甲基纤维素(CMC)/聚(丙烯酰胺-共-甲基丙烯酸钠)(poly(AAm-co-NMR))水凝胶。研究CMC含量对半-IPN水凝胶溶胀率及对甲基紫的吸附性能影响。IPN-0.25、IPN-0.50和IPN-1.00对甲基紫的平衡吸附容量分别为111.0、182.3和237.6 mg/g。分别采用拟一级、拟二级和粒内扩散模型拟合实验数据,结果表明,拟二级动力学模型最符合该体系,其相关系数R2最高,说明水凝胶对甲基紫的吸附主要为化学吸附。     

城市生活垃圾中纤维素含量测定方法优化

对传统硫酸法进行改进,建立适用于城市生活垃圾纤维素含量的测定方法。以脂肪抽提时间、硫酸浓度、水解反应温度、水解反应时间、稀释硫酸浓度、回流时间为考察因素进行6因素5水平正交实验。结果表明,测定纤维素含量的最佳条件为：脂肪抽提时间4h、硫酸浓度70％、水解反应温度30℃、水解反应时间5h、稀释硫酸浓度5％、回流时间3h。优化后纤维素测定条件RSD均小于1．69％,平均回收率98．76％,表明该方法的精度高,可靠行强。     

碱液预处理玉米秸秆的条件优化及添加剂的选择

利用稀NaOH溶液预处理玉米秸秆,以去除木质素,减少半纤维素、纤维素的损失为目的,采用响应曲面法对预处理条件进行优化,得到的最佳预处理条件为:NaOH溶液浓度0.77%(w/w),预处理时间16 h,温度45.6℃。并且,进一步研究了不同添加剂(聚乙二醇、吐温-80和尿素)与NaOH溶液协同作用下秸秆中木质素的去除效果,结果表明尿素与NaOH的混合溶液对木质素去除效果最显著。秸秆在45.6℃,0.77%NaOH和0.2%尿素混合溶液中浸泡16 h后,纤维素回收率为86.33%,半纤维素回收率为69.89%,木质素去除率为64.93%;与原秸秆相比,纤维素含量提高了31.70%,半纤维素含量提高了6.62%,木质素含量减少了46.48%。     

CMC/NI复合材料净化水中的As(Ⅲ)

采用羧甲基纤维素钠(CMC)为包覆材料,通过原位修饰技术改性纳米铁(NI),制得羧甲基纤维素包覆型纳米铁复合材料(CMC/NI)。利用场发射扫描电镜、傅立叶红外光谱仪和X射线衍射仪对CMC/NI复合材料进行表征;以水溶液中As(Ⅲ)的有效去除率为目标,探索了制备条件(铁源种类、包覆质量比CMC/(CMC+Fe)和制备温度等)和反应条件(砷溶液初始p H值、反应温度和复合材料投加量等)对复合材料净化水中As(Ⅲ)的影响。结果表明,改性后的CMC/NI复合材料分散性和抗氧化性得到提高,具有良好的As(Ⅲ)净化能力。以Fe SO4为铁源,包覆比为37%,20℃条件下制备的复合材料,以1.5 g/L加入到温度为30℃,p H为7,初始浓度为2 mg/L的砷溶液中,反应24 h,其As(Ⅲ)去除率可达98%。     

MBFX-8/磁性Fe_3O_4@CMC复合絮凝剂的制备及对Cu~(2+)的去除

以微生物絮凝剂MBFX-8、羧甲基壳聚糖CMC和磁性Fe_3O_4为原料,制备了新型MBFX-8/磁性Fe_3O_4@CMC复合絮凝剂。采用FTIR和XRD对新型复合絮凝剂进行表征。结果表明,羧甲基壳聚糖(CMC)已成功接枝在Fe_3O_4纳米粒子表面,而且MBFX-8也顺利掺入复合絮凝剂中。考察了MBFX-8与Fe_3O_4@CMC的质量比、p H、絮凝剂投加量和静置反应时间对Cu~(2+)去除性能的影响。MBFX-8与Fe_3O_4@CMC的质量比为1∶5时,复合絮凝剂对Cu~(2+)的去除率最好。复合絮凝剂对Cu~(2+)的去除效果与溶液初始p H以及静置反应时间正相关,而与其投加量的增加呈先提高后降低的趋势。当溶液初始p H值为6.5,复合絮凝剂投加量为5 g·L-1,静置反应时间为3 h时,得到最优的Cu~(2+)去除效果,达98.9%。     

Preparation and characterization of modified dual network dust suppression gel based on sodium alginate and soluble starch

Aiming at the problems of complex environment and serious dust pollution in large open-pit coal yards, a dust suppression gel with a dual network structure was prepared by modifying the soluble starch and sodium alginate with iron ions. The changes of functional groups, thermal stability, and morphology structure before and after the reaction were analyzed by FTIR, TG-DSC, and SEM, and the formation mechanism of the dual network was revealed by XPS. Furthermore, the water absorption and water retention experiments proved that the dual network structure is more conducive to water retention than the single-layer network. According to molecular dynamics simulations and contact angle experiments, gel and adsorbed water molecules can approach coal dust molecules on their own to contact, wet, and combine with coal dust. The adhesion test proved that the dust suppression gel with iron ions had better adhesion to dust. The anti-freezing test shows that the dust suppression gel has good anti-freezing performance. The antifreeze test shows that the dust suppression gel still has excellent freeze–thaw resistance at the test temperature of??-20℃. The mechanical property test shows that the dust suppressant gel can prevent the product from being damaged by external force. The acid and alkali resistance experiments showed that the acid and alkali resistance of the gel was improved under the condition of iron ion modification, and the flying of coal powder was effectively prevented. This research provides a new theoretical idea for coal dust control in complex environment.

     

The effects of coal dust on photosynthetic performance of the mangrove, Avicennia marina in Richards Bay, South Africa

Richards Bay, on the northern KwaZulu-Natal coast, is the largest coal exporting port in South Africa. The coal is stored at the Richards Bay Coal Terminal (RBCT) prior to export. Dust from coal operations is a major problem in the Richards Bay area. In this study, we tested the hypothesis that coal dust adversely affects photosynthetic performance of Avicennia marina (Forssk.) Vierh., the dominant mangrove species in the harbour. Photosynthetic performance was determined on 10 trees by measuring carbon dioxide uptake and chlorophyll fluorescence parameters at two elevation sites and on upper and lower leaf surfaces that were covered or uncovered with coal dust. Measurements were made on five clear, sunny days at saturating light (>1,000 micromol m(-2)s(-1)) and high temperature (28-30 degrees C). Coal dust significantly reduced carbon dioxide exchange of upper and lower leaf surfaces by 17-39%, the reduction being generally greater on the lower leaf surface that is covered by a dense mat of trichomes and salt glands. The reduction in carbon dioxide exchange by coal dust was higher at the high elevation site that supported isolated dwarfed trees. The chlorophyll fluorescence data indicated that leaves coated with dust exhibited significantly lower photosystem II (PS II) quantum yield, lower electron transport rate (ETR) through PSII and reduced quantum efficiency of PSII (FvFm). The chlorophyll fluorescence data supported the gas exchange measurements and are consistent with reduced photosynthetic performance of leaves coated with coal dust.     

Coal particle dispersion monitoring system

A monitoring system for coal panicle dispersion at coal storage yards is necessary to meet environmental standards for the operation of coal fired power plants. We have developed a system having three functions as follows:

• 1.(1) To measure coal particle concentrations at the first connecting part of belt conveyors.
• 2.(2) To predict occurrence of coal particle dispersion during stacking.
• 3.(3) To moisten the coal at the second connecting part of belt conveyors when coal particle dispersion occurs.

The generation of coal dispersion is determined by whether or not the hygroscopic moisture is greater than the critical hygroscopic moisture value for each coal type. Coal particle concentrations are measured using dust meters. In this report, the dust meter readings were related to emission rate of coal particle and dustiness index of coarse dust defined by ASTM D547-41 in order to predict occurrence of coal particle dispersion using dust meters.The adaptability of the system to real coal handling facilities was examined by a model which consisted of belt conveyors, a stacker, connecting parts and the monitoring system. As a result of these experiments, it was demonstrated that coal particle dispersion can be suppressed by means of wetting coal in response to dust meter readings.     

粉煤灰沸石负载Ce^3＋／TiO2光催化降解水中的菲和荧蒽

以钛酸四丁酯为前驱体,粉煤灰合成沸石为载体,采用溶胶-凝胶方法,在低温条件下制备了稀土铈掺杂的TiO2光催化剂。利用SEM—EDS、XRD、FTIR对催化剂进行了分析和表征。以高压汞灯为灯源,对多环芳烃菲、荧蒽的降解进行了研究。实验考查了稀土铈掺杂质量分数、催化剂用量、溶液pH、目标物初始质量浓度等因素对光催化降解的影响,研究了其光降解动力学。结果表明,当稀土铈含量为0．5％,催化剂用量为3g／L,pH偏碱性时,催化效果最佳。光催化反应符合Langmuir—Hinshelwood动力学规律,菲、荧蒽的降解过程符合一级反应动力学,反应速率常数分别为0．0126min^-1,0．0099min^-1。     

改性玉米淀粉对Cu2＋、Pb2＋和Zn2＋的吸附特性研究

以玉米淀粉为原料,经过交联、醚化、胺化和亲核加成等步骤合成了一种新型重金属吸附剂——二硫代氨基甲酸改性淀粉（DTCS）。改性淀粉的结构采用红外光谱和扫描电镜进行表征。DTCS是一种性能优良的重金属吸附剂,对Cu2＋、Pb2＋和Zn2＋的饱和吸附容量随着pH（pH=2~6）的增加而增大。在有EDTA络合剂存在和酸性废水pH小于3的情况下,DTCS对Cu2＋、Pb2＋和Zn2＋仍有较高的去除率,分别达到90%、75%和50%以上,说明DTCS在含重金属离子的实际废水体系具有一定的实用价值。     

CaH2对Cu-Ce-La-ZSM-5催化分解NO性能的影响

实验采用一步离子交换法制备Cu-Ce-La-ZSM-5催化剂,然后采用共混法制得Cu-Ce-La-ZSM-5/CaH2催化剂。采用扫描电镜（SEM）,电感耦合等离子体发射光谱（ICP-AES）,X射线衍射（XRD）,红外（FTIR）以及NO吸脱附（NO-TPD）对催化剂进行表征。结果显示CaH2的加入使得催化剂中铜离子存在形式发生变化,催化剂表面变光滑洁净,并且吸附NO能力增强。NO催化分解实验的结果表明CaH2提高了催化剂活性和抗氧性。CaH2助催性是由于其受热分解过程中产生的H2能将Cu^2＋还原为具有催化活性的Cu^＋,同时使催化剂表面洁净光滑更容易吸附NO。     

Review and prospects of mining chemical dust suppressant: classification and mechanisms

Environmental Science and Pollution Research - Coal mine pollution is a serious threat to the mine safe production and occupational health of miners. Chemical dust suppression can effectively...     

铜-胺改性ZSM-5吸附剂的制备及其对NOx的净化机理

以ZSM-5分子筛粉体为原料,成型后负载铜盐和有机胺改性,制备出一种高效脱除氮氧化物的吸附剂。通过改变铜盐、有机胺的含量以及铜盐活化温度使吸附剂的性能得到优化,在实验条件下（NO：初浓度1000mg／m^3,气流2．7L／min）床层对NO2动态吸附的透过时间由改性前的3min提高到90min,并使NO气体的释放得到有效减缓。通过动态吸附实验研究了NO释放时间在负载前后的变化,通过X射线光电子能谱（XPS）和红外分析（FTIR）研究了吸附剂表面铜元素、有机基团等在吸附前后的变化规律,提出了可能的净化机理。     

潞城市大气PM_（10）中化学元素分布特征

利用ICP-AES分析了潞城市采暖期和非采暖期4个不同功能区PM10样品中16种化学元素,对不同元素的时空分布特征进行了研究,并采用富集因子和主成分分析初步研究了潞城市PM10中元素的主要来源。结果表明,潞城市PM10中重金属污染较为严重,且各元素在采暖期的平均浓度均明显高于非采暖期。PM10中Ca、V、Cr、As、Ni、Mn、Cu、Zn、Al和Pb的富集因子EF〉10,主要来源于人为污染;而Na、Mg、Si、Fe和K的EF〈10,除部分来自人为活动外,主要来自土壤风沙等自然来源。主成分分析结果显示,潞城市PM10中元素的主要来源按贡献率大小依次为：煤烟尘和工业粉尘50.39%,自然源34.37%和机动车尾气15.24%。     

纳米TiO2/活性炭复合光催化剂的制备及其对甲醛气体降解

研究了纳米TiO2/活性炭复合光催化剂对空气中典型污染气体甲醛的光催化降解特性。采用扫描电镜（SEM）表征复合催化剂的表面特征。结果显示,经改性后的纳米TiO2在复合催化剂表面分布均匀,呈球状。对甲醛气体的降解实验显示TiO2负载量为1%时对甲醛的去除效果最好,6 h去除率为61.7%。结果显示复合催化剂把甲醛气体分解成CO2,可以直接排空,无二次污染。