Synthesis and characterization of superoleophobic fumed alumina nanocomposite coated via the sol-gel process onto ceramic-based hollow fibre membrane for oil-water separation

Oily wastewater treatment is a global challenge due to the substantial amount of effluent resulted from many industrial and domestic activities. To overcome the challenge of using existing treatment approach and fouling, superoleophobic coatings were fabricated. In this study, a superoleophobic membrane surface was obtained using the sol-gel technique with perfluorooctanoate (PFO), poly (diallyl dimethylammonium chloride) (PDADMAC), and nanoparticles as complex-polymer nanocomposites. The effects of coating cycles on the surface structure, chemical properties, surface chemistry, and oleophobicity of the surface were examined using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and oil contact angle measurement. The results showed that the coated layer successfully adhered to the substrate surface. However, the chemical stability with respect to oil contact angle (OCA) revealed a decline at pH 7 and pH 9 and maintained stability at pH 3. Besides, oil flux at 63.0 L/m². h was achieved for PDADMAC-Al₂O₃/44 wt% PFO and the highest separation efficiency of 98% was obtained. Furthermore, the oil rejection decreases as the oil concentration increases from 1 to 3 g/L. OCA of 155° was obtained after 5 coating cycles. Apart from mitigating substrate fouling, the superoleophobic and superhydrophilic coating can be applied to a ceramic-based hollow fibre membrane and efficiently used for the separation of oil from oily wastewater.     

Preparation and antifouling performance of thin inorganic ultrafiltration membrane via assisted sol-gel method with different composition of dual additives

A novel TiO₂ thin film was prepared on the ceramic hollow fiber by the sol-gel method using poly(vinylpyrrolidone) (PVP) and polyvinyl alcohol (PVA) as additives. SEM images verified the formation of TiO₂ layer with various thickness using different composition of titania sols. The effect of the PVP and PVA contents on the TiO₂ sol properties, the separation and the antifouling performance of the ultrafiltration membranes were investigated thoroughly. When the contents of PVP and PVA were 1.0 wt% and 0.8 wt%, respectively, the resultant membrane showed a thickness of 0.55 μm with a pure water flux of 255 L m^?2 h^?1. In addition, the adherent foulant bovine serum albumin was applied to evaluate the antifouling performance. During the three fouling-recovery cycles, the flux recovery ratio and the flux decay ratio maintained about 99% and 30%. The BSA flux and rejection were still 169 L m^?2 h^?1 and 96.9% after the cycles, indicating a superior antifouling property.     

Experimental investigations of enhanced glow based on a pulsed hollow-cathode discharge

In this work, the pulsed hollow cathode discharges at low pressure argon with an axial magnetic field were studied. The results indicate that the pulsed discharge is operated in an enhanced glow(EG) mode. Under the same conditions, the discharge current of the pulsed discharge is two or three orders higher than that of the direct current discharge. The spatial and temporal evolution of the light emission shows that, the current fluctuation at the rising edge of the pulse plays an important role for the EG discharge of pulsed hollow cathode, which forms a high-density, highcurrent and long-distance plasma column outside the cavity.     

低温水等离子体活化和表面接枝DMAE聚氯乙烯中空纤维膜研究

采用低温水等离子体技术，在三通道聚氯乙烯(PVC)膜表面接枝了甲基丙烯氧基苄基二甲基氯化铵(DMAE)单体，增强了膜亲水和抗菌性能。通过红外分析，表明DMAE成功接枝到了PVC膜上，水通量提高两倍，PVC-ir-H₂O膜(通过水等离子体处理的膜)对牛血清蛋白(BSA)的吸附能力下降67%，对BSA溶液的通量从7.7提高至40 kg?m^-2?h^-1，并且对BSA的截留能力不变。通过静态及动态抗菌实验，接枝后的PVC膜（PVC-g-PMAE膜）抗菌率达到100%，膜组件运行中的抗菌率也达到82%以上。在保证细菌截留率100%的同时，其渗透通量提高三倍。该膜表面修饰工程技术能实现膜表面的均一化改性，且绿色环保、操作简便、成本低，改性膜在饮用水处理领域，尤其是家用净水器中展现了很好的应用前景。     

Ni-P/HZSM-5催化木质素降解制备酚类化学品

采用Ni-P复合改性HZSM-5催化剂催化木质素降解制备高附加值的单酚类化学品，探讨了催化剂种类、金属负载量、反应温度、反应时间以及溶剂种类对木质素催化降解制备酚类化合物的影响。同时采用X射线衍射仪（XRD）、比表面积和孔径分析仪（BET）、化学吸附仪（NH₃-TPD）、热重分析仪（TG）以及气相色谱质谱联用仪（GC/MS）对催化剂以及液相产物进行分析表征，同时探讨其催化失活以及再生机制。结果表明：Ni、P高度分散在HZSM-5催化剂的表面，Ni的添加有效地弱化了C－C键，致使β-O-4和α-O-4发生断裂，有效地提高了木质素加氢解聚的活性，减少了焦炭的生成，但催化剂的再生水热稳定性较差，重复使用性较低。当采用甲醇为供氢试剂，在反应温度为220℃，氢气压力为2MPa，反应时间为8h，催化剂负载量为10%，NaOH为共催化剂时，其木质素的转化率为98.6%，酚类化合物的含量达到74.97%。产物以苯酚、愈创木酚和紫丁香酚为主，低温促进了紫丁香酚的产生。     

Bamboo biochar-catalytic degradation of lignin under microwave heating

Abstract

Lignin biochar-catalytic depolymerization using biochar Fe-600, Fe-800, Ni-600, Ni-800 catalysts under microwave-heating (180?°C for 30?min) was explored in an ethanol/formic acid (1:1) media. Non-catalyst depolymerization was also studied and compared with the biochar-catalysts results. Characteristics of the bio-char catalysts were analyze by BET, XRD, and FT-IR. GPC, FT-IR, and MALDI-TOF MS spectrometry were also used to characterize the depolymerization products. The experimental results showed that the S_BET, V_t, and V_mec and average pore diameter of the biochars are considerably dependent on the preparation temperature and type of cation (Ni²⁺ or Fe³⁺). The maximum yield of bio-oil product was obtained as 85?wt% with the addition of biochar Ni-600 and the total amount of oligomers or monomers with a molecular weight of 164 to 446 reaches 80.4%.     

木质素基表面活性剂研究现状

木质素作为一种天然高分子化合物，其来源丰富，可以用来代替石油资源制备表面活性剂，缓解当前石油资源枯竭的问题。常见的木质素基表面活性剂有阳离子表面活性剂、阴离子表面活性剂、两性离子表面活性剂以及非离子表面活性剂。木质素基表面活性剂在工业领域具有广泛的应用范围，可以作为染料分散剂、混凝土减水剂、沥青乳化剂以及原油采集过程中的驱油剂等。木质素基表面活性剂的开发利用为生物质产品的高值化利用开辟了一条新的路径。