GA-g-PAMPS/AA/ST凝胶的制备及对亚甲基蓝吸附性能

采用微波辐射技术,通过接枝共聚反应制备了阿拉伯胶（GA）-g-2-丙烯酰胺-2-甲基丙磺酸（AMPS）/丙烯酸（AA）/海泡石黏土（ST）（GA-g-PAMPS/AA/ST）复合水凝胶,利用FTIR、XRD、SEM对复合水凝胶进行了表征,研究了水凝胶对水溶液中亚甲基蓝（MB）染料的吸附性能.结果显示：GA、ST和AA与AMPS发生了接枝共聚反应,形成具有均匀三维网络结构的复合水凝胶.0.025g水凝胶可以使体积为50mL、pH值为6.4、浓度为600mg/L的MB溶液的吸附量和吸附率分别达1146mg/g和95.5%,水凝胶具有较好的重复利用性能.Freundlich等温模型和准二级动力学模型能更好地描述吸附过程.热力学研究表明水凝胶对亚甲基蓝吸附是自发、吸热和不可逆的过程.该水凝胶可用作阳离子染料和阳离子型污染物的潜在候选生物质吸附剂.     

Lightweight Concrete Containing an Alkaline Resistant Starch-Based Aquagel

Starch aquagel-based lightweight concrete has properties similar to those of other lightweight concrete products. However, starch aquagels are unstable in the strongly alkaline conditions typical of Portland Cement-based concrete and may interfere with the setting process. The effect of alkali treatments on the physical, mechanical, and functional properties of starch aquagels and aquagels from starch/polymer blends was investigated. Starch was blended at 100–115°C in a twin-screw extruder with five different polymers to determine whether the blends improved alkaline resistance. Polymer blends containing 5%, 15%, and 30% of the polymer hydrated and formed aquagels when equilibrated in water for 24 h. However, equilibrium moisture content was lower for the blends compared to the starch control. Aquagels equilibrated in 0.15 N NaOH swelled, lost compressive strength and had greater than 90% moisture. The blend of starch and 30% PVOH absorbed less moisture and was more resistant to alkaline dissolution in 1 N NaOH than the other blends tested making it a more suitable material for aquagel-based concrete. The moisture content of starch-based aquagels and mixing time were critical factors in determining setting times. The size of aquagel blends had a minor effect on density and compressive strength.     

铁锰复合氧化物/壳聚糖珠:一种环境友好型除磷吸附剂

采用两步法制备了一种环境友好型除磷基吸附剂——铁锰复合氧化物/壳聚糖珠(FMCB),对其进行了表征,并对其磷吸附行为进行了系统研究.表征结果表明,该吸附剂为多孔纤维结构,比表面积为248 m~2·g~(-1),孔容为0.37 m~3·g~(-1).吸附实验结果表明,FMCB对磷的吸附容量远高于纯的壳聚糖颗粒,且Langmuir模型能更好地拟合FMCB对磷的吸附,最大吸附量为13.3 mg·g~(-1)(pH 7.0);准二级动力学模型能更好地拟合FMCB对磷吸附的动力学实验数据;溶液pH对磷的吸附影响较大,随着pH的增大,磷的吸附量逐渐降低;共存的Ca~(2+)和Mg~(2+)对磷吸附略有促进,而共存阴离子对磷吸附具有抑制作用,影响大小顺序为:SiO_3~(2-)CO_3~(2-)SO_4~(2-)≥Cl~-.吸附磷后的FMCB可用NaOH溶液进行脱附再生,并可重复使用.在进水磷初始浓度为3 mg·L~(-1)条件下,吸附达到穿透时(出水磷浓度达0.5 mg·L~(-1)),可处理约800个柱体积的模拟含磷废水.     

污水处理用聚乙烯醇凝胶的制备及结构与性能

采用化学交联法研究制备聚乙烯醇(PVA)固定化微生物凝胶用于污水处理,通过对固化剂种类、固化时间等制备工艺研究,获得了具有较高力学强度和通透性的PVA凝胶小球.对固化剂与PVA分子间相互作用、PVA凝胶交联程度及凝胶形貌进行了探讨分析.将所制备PVA凝胶小球用于污水处理,其COD去除率可达90%以上.     

着床后引燃对电弧迸溅熔珠组织特征的影响*

为探究迸溅熔珠着床后的热交换过程对其组织特征的影响,建立基于着床后高温迸溅熔珠的动态测温方法,从而揭示迸溅熔珠着床后引燃与否对其组织特征形成的影响规律。研究结果表明:引燃可燃物的熔珠受火焰热反馈和铜氧化放热的共同作用,着床后其温度出现反复波动,延长迸溅熔珠的冷却凝固时间,组织呈等轴状;无法引燃可燃物的熔珠在可测范围内,短暂升温后降温速率持续上升,组织更易呈现树枝状或胞状。研究结果可为准确认定电气故障电弧迸溅熔珠引发火灾提供技术支持。     

回收粉煤灰磁珠在污水处理中的应用

从粉煤灰综合利用角度,探时利用回收粉煤灰中磁珠作磁种,用高梯度磁分离技术进行污水处理的可行性,进一步研究了粉煤灰磁珠粒度组成对污水处理效果的影响。     

用聚(丙烯酸/丙烯酰胺)水凝胶吸附单价阳离子染料的研究

研究了用聚 (丙烯酸 丙烯酰胺 ) [P(AAc AAm) ]水凝胶对较高较大浓度范围 (10 -6— 10 -2 mol L)的阳离子染料碱性藏花红 (SafranineT)溶液的吸附过程和水凝胶经解吸后的再吸附性质 .实验结果表明 :增大P(AAc AAm)水凝胶的交联度和电荷比值有利于吸附过程的进行 ,并强化了引发过程 (initiationprocess)而抑制了协同过程 (cooperativeprocess) .水凝胶经解吸后 ,其吸附能力大大地增强 ,复合度 (β)超过 1,约为 1 5 ,此时 ,协同性和染料分子间的疏水相互作用起了主要作用     

氧化石墨烯-零价铁-聚乙二醇-海藻酸钠凝胶球活化过硫酸钠降解水中的偏二甲肼

以海藻酸钠(SA)、聚乙二醇(PEG)、氧化石墨烯(GO)和零价铁(ZVI)为原料制备了氧化石墨烯-零价铁-聚乙二醇-海藻酸钠凝胶球(GZPS),用于活化过硫酸盐(PDS)降解水中的偏二甲肼(UDMH)。对GZPS进行了表征,并优化了GZPS的制备工艺。实验结果表明:对UDMH去除率影响因素的主次顺序为:w(PEG) w(SA)w(GO)w(ZVI);GZPS的最佳制备工艺为SA、PEG、GO、ZVI的质量分数分别为5%,3%,0.3%,2%;在UDMH质量浓度为100mg/L、PDS加入量为4mmol/L、GZPS加入量为60g/L、反应温度为35℃、反应时间为80 min的条件下,UDMH的去除率达85%以上。GZPS活化PDS降解UDMH的反应符合准一级动力学,Fe溶出量仅为Fe-GO-PDS体系的12.7%,重复使用4次后对UDMH的去除率仍在65%以上。     

Nitrate removal from aqueous solutions by magnetic cationic hydrogel: Effect of electrostatic adsorption and mechanism

Excessive nitrate(NO_3~-) is among the most problematic surface water and groundwater pollutants.In this study,a type of magnetic cationic hydrogel(MCH) is employed for NO_3~-adsorption and well characterized herein.Its adsorption capacity is considerably pHdependent and achieves the optimal adsorption(maximum NO_3~--adsorption capacity is95.88±1.24 mg/g) when the pH level is 5.2-8.8.The fitting result using the homogeneous surface diffusion model indicates that the surface/film diffusion controls the adsorption rate,and NO_3~-approaches the center of MCH particles within 30 min.The diffusion coefficient(D_s) and external mass transfer coefficient(k_F) in the liquid phase are1.15 × 10~(-6) cm~2/min and 4.5 × 10~(-6) cm/min,respectively.The MCH is employed to treat surface water that contains 10 mg/L of NO_3~-,and it is found that the optimal magnetic separation time is 1.6 min.The high-efficiency mass transfer and magnetic separation of MCH during the adsorption-regeneration process favors its application in surface water treatment.Furthermore,the study of the mechanism involved reveals that both-N~+(CH_3)_3 groups and NO_3~-are convoluted in adsorption via electrostatic interactions.It is further found that ion exchange between NO_3~-and chlorine occurs.     

磁性壳聚糖凝胶球固定厌氧铁氨氧化菌对废水氨氮去除的影响

厌氧铁氨氧化(ammonium oxidation coupling with iron reduction,Feammox)反应是一种在厌氧条件下,由厌氧铁氨氧化菌驱动,以三价铁为电子受体,氧化氨氮的生物化学途径,它可以用于去除水体中的氨氮.为提高厌氧铁氨氧化菌对氨氮废水处理效果,采用"氢氧化钠共沉淀-溶胶-凝胶"法制备粒径为1~5mm的磁性壳聚糖凝胶球(magnetic chitosan hydrogel beads,MCHBs),将厌氧铁氨氧化菌固定,研究其对废水中氨氮去除效果和影响因素,并与游离厌氧铁氨氧化菌对废水氨氮去除效率作对比.制备的MCHBs进行X射线衍射(XRD)和振动样品磁强(VSM)等表征分析.结果表明,MCHBs为铁磁性、结晶度高,饱和磁化强度达29.46 emu·g~(-1).MCHBs固定厌氧铁氨氧化菌比游离菌具有更高的氨氧化和铁还原速率,平均增幅为42.96%和20.75%,以MCHBs(1~2 mm)固定厌氧铁氨氧化菌的效果最显著(P0.05).进一步研究发现,不适宜氨氮浓度、温度和pH下,MCHBs(1~2 mm)固定厌氧铁氨氧化菌氧化氨氮的能力均比游离菌高.初始氨氮浓度60.00 mg·L~(-1)、温度25℃和pH 4.50时,厌氧铁氨氧化效果较好,主要产物为硝态氮和二价铁,16 d时MCHBs(1~2 mm)固定厌氧铁氨氧化菌对氨氮去除率高达53.62%.这些结果都表明以MCHBs固定厌氧铁氨氧化菌后,能起到增强厌氧铁氨氧化反应去除废水氨氮的目的.