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.     

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.     

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     

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.     

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.     

Preparation of porous semi-IPN temperature-sensitive hydrogel-supported nZVI and its application in the reduction of nitrophenol

Nanoscale zero-valent iron(n ZVI) particles supported on a porous, semi-interpenetrating(semi-IPN), temperature-sensitive composite hydrogel(PNIPAm-PHEMA). n ZVI@PNIPAmPHEMA, was successfully synthesized and characterized by FT-IR, SEM, EDS, XRD and the weighing method. The loading of nZVI was 0.1548 ± 0.0015 g/g and the particle size was30–100 nm. NZVI was uniformly dispersed on the pore walls inside the PNIPAm-PHEMA.Because of the well-dispersed n ZVI, the highly porous structure, and the synergistic effect of PNIPAm-PHEMA, nZVI@PNIPAm-PHEMA showed excellent reductive activity and wide p H applicability. 95% of 4-NP in 100 m L of 400 mg/L 4-NP solution with initial p H 3.0–9.0 could be completely reduced into 4-AP by about 0.0548 g of fresh supported n ZVI at 18–25 °C under stirring(110 r/min) within 45 min reaction time. A greater than 99% 4-NP degradation ratio was obtained when the initial p H was 5.0–9.0. The reduction of 4-NP by nZVI@PNIPAm-PHEMA was in agreement with the pseudo-first-order kinetics model with Kobsvalues of 0.0885–0.101 min-1.NZVI@PNIPAm-PHEMA was able to be recycled, and about 85% degradation ratio of 4-NP was obtained after its sixth reuse cycle. According to the temperature sensitivity of PNIPAmPHEMA, n ZVI@PNIPAm-PHEMA exhibited very good storage stability, and about 88.9%degradation ratio of 4-NP was obtained after its storage for 30 days. The hybrid reducer was highly efficient for the reduction of 2-NP, 3-NP, 2-chloro-4-nitrophenol and 2-chloro-4-nitrophenol. Our results suggest that PNIPAm-PHEMA could be a good potential carrier, with n ZVI@PNIPAm-PHEMA having potential value in the application of reductive degradation of nitrophenol pollutants.     

Enhanced adsorption of Methylene Blue from aqueous solution by chitosan-g-poly （acrylic acid）/vermiculite hydrogel composites

A series of chitosan-g-poly (acrylic acid)/vermiculite hydrogel composites were synthesized and used as adsorbents for the investigation of the e ect of process parameters such as vermiculite content, pH of dye solution, contact time, initial concentration of dye solution, temperature, ionic strength and concentration of surfactant sodium dodecyl sulfate on the removal of Methylene Blue (MB) from aqueous solution. The results showed that the adsorption capacity for dye increased with increasing pH, contact time and initial dye concentration, but decreased with increasing temperature, ionic strength and sodium dodecyl sulfate concentration in the present of the surfactant. The adsorption kinetics of MB onto the hydrogel composite followed pseudo second-order kinetics and the adsorption equilibrium data obeyed Langmuir isotherm. By introducing 10 wt.% vermiculite into chitosan-g-poly (acrylic acid) polymeric network, the obtaining hydrogel composite showed the highest adsorption capacity for MB, and then could be regarded as a potential adsorbent for cationic dye removal in a wastewater treatment process.     

壳聚糖水凝胶制备及其对Pb~(2+)吸附性能研究

以壳聚糖为原料,丙烯酸为接枝单体,N,N'-亚甲基双丙烯酰胺作交联剂制备了一种新型壳聚糖水凝胶。通过FTIR、SEM、热重和能谱分析对壳聚糖水凝胶进行表征,并在此基础上考察其对Pb~(2+)的吸附行为。实验结果表明:所制备的壳聚糖水凝胶是一种性质稳定的多孔结构高分子聚合物,分子中含有大量的—NH_2、—OH、—COOH等活性基团,可通过螯合、离子交换或形成离子对等方式吸附金属离子,对Pb~(2+)具有较高的吸附去除效率。     

高分子改性黄原胶/羟基磷灰石复合水凝胶的制备及其吸附金属离子性能

以黄原胶为接枝骨架,丙烯酸为单体,羟基磷灰石为无机组分,通过氧化还原聚合反应,制备了高分子改性黄原胶/羟基磷灰石复合水凝胶(XG-g-PAA/HAP).红外光谱和扫描电镜表征发现,在低温条件下(50℃)成功制备了XG-g-PAA/HAP.将XG-g-PAA/HAP用作水体重金属离子吸附剂,结果表明:当pH1时,XG-g-PAA/HAP吸附容量较小,随着pH增大,吸附容量快速增大,当pH4时,吸附容量达到平衡;90%以上的金属离子在30 min内可被清除.当[Cu~(2+)]=300 mg·L~(-1)和[Pb~(2+)]=600 mg·L~(-1)时,XG-g-PAA/HAP吸附容量达到最大值.重复吸附-脱吸附5次后,吸附容量仍可保持初始的80%,所制备的XG-g-PAA/HAP有望成为一种有效的水体重金属离子吸附剂.