海藻酸钠-刺槐豆胶复合凝胶珠吸附孔雀绿简

以刺槐豆胶、海藻酸钠为材料制备复合凝胶珠，利用红外光谱、热重分析对其进行表征，探讨孔雀绿浓度、吸附时间及pH对复合凝胶珠吸附孔雀绿的影响。红外光谱和热重分析表明，复合凝胶珠制备成功且热稳定性介于刺槐豆胶和海藻酸钠之间。复合凝胶珠对孔雀绿的吸附在5 h后达到平衡，pH=6为最佳吸附pH，相同条件下复合凝胶珠对孔雀绿的吸附作用优于活性炭，其对孔雀绿的吸附行为符合Freundlich吸附等温方程和颗粒内扩散模型。海藻酸钠-刺槐豆胶复合凝胶珠有望成为新的处理印染废水的吸附剂。     

包埋碳纳米管海藻酸钠凝胶球吸附苯酚的研究

研究了水溶液中碳纳米管及包埋固定于海藻酸钠凝胶球中的碳纳米管吸附苯酚的特性,测定了温度、pH值、转速等因素对吸附的影响,并对吸附剂进行了热脱附再生.绘制了吸附等温线,对吸附机理进行探讨.结果表明,碳纳米管及包埋于海藻酸钠凝胶球中的碳纳米管对苯酚的吸附平衡受pH和转速影响不显著,受温度影响显著,简单的热再生即有很好的再生效果.通过方程拟合,2种吸附剂对苯酚的吸附均符合Langmuir和Freundlich型吸附等温式.     

海藻酸钠-聚氧化乙烯凝胶球去除废水中重金属离子的研究

研究了海藻酸钠浓度及固化时间对海藻酸钠-聚氧化乙烯(SA-PEO)凝胶球性能的影响以及采用SA-PEO凝胶球对溶液中3种重金属离子(Pb2 ,Cu2 、Cd2 )进行吸附实验的研究.结果表明,2.0%(质量分数)的SA溶液制成的凝胶球性能较好,固化时间对重金属去除率影响较小,但随着固化时间的增加,SA-PEO凝胶球的直径逐渐缩小,紧密程度和机械强度逐渐增加;在重金属离子溶液pH为4～6时,SA-PEO凝胶球对重金属离子去除率较高;SA-PEO凝胶球对不同重金属离子吸附效果为pb2 >Cu2 >Cd2 ;多种重金属离子共存使得SA-PEO凝胶球对Pb2 和Cd2 的吸附受一定程度的抑制,而对Cu2 吸附能力有所增强,说明SA-PEO凝胶球对重金属离子吸附有选择性;1.00 mol/L的HCl溶液对Pb2 的解吸效果较好,解吸再生后的SA-PEO凝胶球可以重复利用.     

羧甲基化壳聚糖/海藻酸钠凝胶的制备及其对阳离子染料的吸附研究

采用离子交联法制备羧甲基化壳聚糖/海藻酸钠(CM-CS/SA)凝胶,利用红外光谱、扫描电镜和热重分析仪对CM-CS/SA凝胶的结构和形貌进行表征。以CM-CS/SA凝胶为吸附剂对3种阳离子染料(亚甲基蓝、品红和结晶紫)进行吸附研究,考察了吸附时间、吸附剂用量、染料初始浓度和吸附温度对吸附效果的影响。结果表明,CM-CS/SA凝胶对3种阳离子染料的吸附过程可用准二级动力学方程和粒子内扩散方程表达,根据Langmuir等温吸附模型分析,该吸附体系属于单分子层吸附,CM-CS/SA凝胶对亚甲基蓝、品红和结晶紫的最大吸附容量分别为2.50、3.17、1.78mg/g。     

壳聚糖/海藻酸钠复合絮凝剂的吸附性能

采用壳聚糖和海藻酸钠制备新型复合絮凝剂,通过正交实验考察复合絮凝剂投加量、搅拌时间、絮凝温度及pH值等因素对曙红染料废水吸附效果的影响,并采用红外光谱对产品进行表征。结果表明:最佳吸附条件为复合絮凝剂投加量0.30 g,pH值为5.00,搅拌时间为2.0 h,絮凝温度25℃时,脱色率可达97.52%。复合絮凝剂对曙红溶液的吸附等温曲线遵循Freundlich吸附等温式和Langmuir等温吸附式。     

纤维素/硅藻土复合气凝胶的吸附性能

以纤维素与硅藻土为原料制备纤维素/硅藻土复合气凝胶。研究了影响纤维素/硅藻土复合气凝胶吸附的因素,以及复合气凝胶吸附亚甲基蓝的等温曲线、动力学与热力学特性。结果表明,纤维素/硅藻土复合气凝胶中硅藻土最佳含量为0.5 g,随着pH值的提高,纤维素/硅藻土复合气凝胶吸附量增大,碱性条件下最好。纤维素/硅藻土复合气凝胶的吸附量符合Langmuir及伪二级动力学模型,最大吸附量为68.399 5 mg/g。热力学研究表明,纤维素/硅藻土复合气凝胶吸附亚甲基蓝是自发、放热的物理吸附过程。     

可见光/H2 O2/海藻酸铁非均相催化降解吖啶橙的研究

由海藻酸钠和氯化铁反应制备了海藻酸铁凝胶小球催化剂,考察了该催化剂的吸附和可见光下催化降解吖啶橙的性能.结果表明催化剂的吸附能力随pH升高而提高,且催化剂用量为40个凝胶小球时,可见光下吖啶橙能够在较宽pH值范围内脱色,脱色速率随H2O2的用量增加而增加,该反应符合Arrhenius规律,其表观活化能为49.6 kJ/mol.自由基清除剂的加入不会降低脱色速率,表明催化反应不是羟基自由基的机理,而与高活性的类{ Fe(Ⅳ)=O}高价铁中间产物有关.     

海藻酸钠-聚氧化乙烯包埋活性炭去除废水中铜离子的研究

研究了海藻酸钠(SA)-聚氧化乙烯(PEO)包埋活性炭制备凝胶球的最佳工艺。以铜离子去除率为指标,通过单因素试验和响应面分析试验,研究pH=9时,SA、PEO、活性炭及CaCl_2添加量对铜离子去除率的影响。试验得出凝胶球的最佳制备工艺:SA、PEO、CaCl_2和活性炭添加量分别为1.50%(质量分数,下同)、0.20%、6.00%、0.70%。利用最佳制备工艺下制备的凝胶球进行持续3 d的铜离子吸附试验,铜离子去除率达到95.57%。     

生物炭-海藻酸钠联合固定化小球藻去除水中的氨氮

以海藻酸钠为包埋材料,生物炭为添加剂,固定小球藻,制得生物炭-海藻酸钠联合固定化小球藻胶球,并将其用于水中氨氮的去除。实验结果表明:生物炭-海藻酸钠联合固定化小球藻具有生物炭吸附和小球藻吸收协同作用,促进了小球藻的生长和水中氨氮的去除,且氨氮的去除率随着胶球加入量和胶球粒径的增加而提高。生物炭-海藻酸钠联合固定化小球藻胶球制备最优方案为:生物炭浓度为0.26 g·L~(-1)、海藻酸钠质量分数为1.8%、胶球中藻细胞密度为3.0×10~6个·mL~(-1)、CaCl_2质量分数为1%;胶球重复使用一次的氨氮去除率可达66.87%。生物炭促进了固定化微藻对高浓度氨氮废水的资源化利用。     

可见光/H2 O2/海藻酸铁非均相催化降解吖啶橙的研究

由海藻酸钠和氯化铁反应制备了海藻酸铁凝胶小球催化剂,考察了该催化剂的吸附和可见光下催化降解吖啶橙的性能.结果表明催化剂的吸附能力随pH升高而提高,且催化剂用量为40个凝胶小球时,可见光下吖啶橙能够在较宽pH值范围内脱色,脱色速率随H2O2的用量增加而增加,该反应符合Arrhenius规律,其表观活化能为49.6 kJ/mol.自由基清除剂的加入不会降低脱色速率,表明催化反应不是羟基自由基的机理,而与高活性的类{ Fe（Ⅳ）=O}高价铁中间产物有关.     

Adsorption of Cu and Mn on covalently cross-linked alginate gel beads

The covalently cross-linked alginate gel beads were prepared by the reactions of Ca(2+)-doped alginate gel beads, which were formed by spraying a viscous alginate solution into a calcium chloride solution, with cyanogen bromide and following 1,6-diaminohexane. The cross-linking of alginate matrix decreased the mean bead diameter by about 30% and made the beads durable in some extent under alkaline conditions. The adsorption of metal ions on the covalently cross-linked alginate gel beads was rapid and reached at equilibrium within 30 min at 25 degrees C. Adsorption isotherms of Cu(II), Mn(II), and Ca2+ on the beads possessed a stepwise shape, which was firstly determined by Rorrer et al. [Ind. Eng. Chem. Res. 32 (1993) 2170] for cross-linked chitosan gel beads and explained by a pore-blockage mechanism. Higher selectivity was determined against Cu(II) over Mn(II) and Ca2+, especially at a low concentration region. These metal adsorption profiles for the covalently cross-linked alginate gel beads was almost the same as those for the un-cross-linked beads, indicating that the cross-linking reactions were performed without interfering the adsorption characteristics of alginate gel beads.     

黄原胶辐射接枝共聚物对Cd^2＋的吸附研究

利用^60Co-γ为辐射源,在氮气保护下对黄原胶（XG）和丙烯酰胺（AM）进行共辐射,制备黄原胶/丙烯酰胺接枝共聚物（XG-g-AM）。研究了XG-g-AM对Cd^2＋的吸附行为,利用红外光谱（IR）、热重分析（TGA）、X射线衍射仪（XRD）对接枝共聚物及吸附产物进行表征。结果表明：XG-g-AM对Cd^2＋离子吸附等温线符合Freund lich等温方程,吸附Cd^2＋使XG-g-AM结晶结构被进一步破坏,结晶度下降。25℃下,Cd^2＋浓度20 mmol/L时,吸附时间100 m in,平衡吸附量为0.835mmol/g。     

改性TiO_2光催化降解三苯甲烷类污染物

以硫酸钛为原料采用水热法制备了掺Fe3＋TiO2晶体粉末,采用X射线衍射仪（XRD）对样品的结构进行了表征。在可见光条件下,用溴酚蓝、甲基绿、甲基蓝、孔雀石绿、甲基紫和碱性品红等6种典型三苯甲烷类化合物为目标降解物,研究了以自制的掺Fe3＋TiO2晶体粉末对它们的催化降解作用。实验结果表明,制备的掺Fe3＋TiO2晶体属于锐钛矿型。6种化合物的光催化降解反应遵循拟一级动力学规律,且可用Langmuir-Hinshelwood（L-H）动力学模型描述,其表观反应速度常数（k）的大小顺序为：溴酚蓝〈甲基绿〈甲基蓝〈孔雀石绿〈甲基紫〈碱性品红,大小变化次序与其半衰期t1/2成反比,并从分子结构上对它们的降解规律进行定性解释。     

聚（丙烯酸-co-丙烯酰胺）/膨润土/腐植酸钠三维网络凝胶吸附剂对Cd^2＋吸附性能研究

制备了一种聚（丙烯酸-co-丙烯酰胺）/膨润土/腐植酸钠三维网络凝胶吸附剂,重点考察了吸附剂对Cd2＋吸附的pH依赖性、吸附动力学和吸附等温线。结果表明,Cd^2＋溶液pH值对吸附容量有较大影响。在pH=8、吸附时间30 min、Cd^2＋溶液初始浓度0.02 mol/L和吸附剂用量0.10 g的条件下,吸附剂对Cd2＋的饱和吸附量可达294.7 mg/g。与膨润土相比,三维网络凝胶吸附剂具有更高的吸附容量和更快的吸附速率。     

Preparation of alginate-chitosan hybrid gel beads and adsorption of divalent metal ions

Naturally occurring polysaccharides such as alginic acid and chitosan have been recognized as one of the most effective adsorbents to eliminating low levels of heavy metal ions from waste water stream. The present study intended to use alginic acid and chitosan simultaneously, which are expected to form a rigid matrix structure of beads due to electrostatic interaction between carboxyl groups on alginic acid and amino groups on chitosan, and to prepare alginate-chitosan hybrid gel beads. This could be achieved for the first time by using water-soluble chitosan, which was obtained by deacetylating chitin to 36-39% degree. The water-soluble chitosan dissolved in water could remain in solution in the presence of sodium alginate, and the homogeneous solution of chitosan and alginate was dispensed into a CuCl2 solution to give gel bead particles. The resultant beads were then reinforced by a cross-linking reaction of aldehyde groups on glutaraldehyde with amine groups on the chitosan. The cross-linking reaction made the beads durable under acidic conditions. The adsorption of Cu(II), Co(II), and Cd(II) on the beads was significantly rapid and reached at equilibrium within 10 min at 25 degrees C. Adsorption isotherms of the metal ions on the beads exhibited Freundlich and/or Langmuir behavior, contrary to gel beads either of alginate or chitosan showing a step-wise shape of adsorption isotherm.     

粉煤灰微波改性及其对Cr~（6＋）的吸附特性

将粉煤灰（fly ash,FA）微波辐照制得微波改性粉煤灰（MFA）,选择用H2SO4、NaOH和Ca（OH）2对MFA进行化学改性制得微波化学改性粉煤灰（MMFA）,结果表明,用2 mol/L NaOH并按与MFA的质量体积比为1∶4制得的MMFA对Cr6＋的吸附去除效果最好,与原灰相比,去除率显著增强。研究了NaOH改性MMFA对废水中Cr6＋的吸附性能。动力学研究结果表明,MMFA对Cr6＋的吸附动力学符合二级吸附动力学速率方程,吸附受颗粒内扩散过程控制。热力学研究结果表明,在25、35和45℃下MMFA对Cr6＋的等温吸附行为均可用Langmuir方程、Freundlich方程和线性方程描述,所得热力学参数吸附自由能（ΔG）、吸附焓（ΔH）和吸附熵（ΔS）均为负值,说明MMFA对Cr6＋的吸附过程为自发进行的放热吸附过程。     

Fe3+(NTA)还原菌的固定化小球制备及还原特性

采用海藻酸钠包埋驯化得到的优势铁还原菌，用于还原络合吸收法脱除NOx过程中形成的中间副产物Fe³⁺(NTA)。结果表明，最佳包埋条件为海藻酸钠质量浓度4%，菌体质量浓度0.2%，CaCl₂质量浓度3%，此条件下制备的小球还原性能好，在微生物用量为20 g（湿重）/L时还原10 mmol/L Fe³⁺(NTA)，经12 h反应后还原率达到96.1％，而相同条件下游离微生物的还原率仅为11.8％，但反应16 h后游离微生物与固定化小球的还原率相近，均为97％左右。但此法制备的小球机械强度不高，溶胀、破裂现象严重。通过添加聚乙烯醇和硅藻土改良固定化小球，可强化小球的机械强度、降低小球的溶胀及破裂现象，对Fe³⁺(NTA)的还原效果也较改良前的小球有所提高，两者最佳添加量均为20 g/L。改良后的小球与游离微生物相比，耐酸性增强，在pH=5的条件下，仍具有79.8％的还原效率，远高于相同条件下游离微生物的39.5％，但对温度的适应范围两者基本一致。     

Effect of immobilized microalgal bead concentrations on wastewater nutrient removal

A unicellular green microalga, Chlorella vulgaris, entrapped in calcium alginate as algal beads were employed to remove nutrients (N and P) from simulated settled domestic wastewater. A significantly higher nutrient reduction was found in bioreactors containing algal beads (at concentrations ranging from 4 to 20 beads ml(-1) wastewater) than the blank alginate beads (without algae). A complete removal of NH(4)(+)-N and around 95% reduction of PO(4)(3-)-P was achieved within 24 h of treatment in bioreactors having the optimal algal bead concentration (12 beads ml(-1), equivalent to 1:3 algal beads:wastewater, v/v). The NH(4)(+)-N removal was significantly lower at low (around 4 beads ml(-1)) and high (>15 beads ml(-1)) algal bead concentrations. On the other hand, the effect of bead concentration on phosphate removal was less obvious, and bead concentrations ranging from 8 to 20 beads ml(-1) showed comparable percentages of phosphate reduction. Algal uptake and adsorption on alginate gels were found to be the major processes involved in the removal of N and phosphate in the present study. In addition, NH(4)(+)-N could be lost via ammonia volatilization while PO(4)(3-)-P was removed by chemical precipitation, as alkaline pH was recorded in the immobilized microalgal treatment system.