Psychrophilic hydrogen production from petrochemical wastewater via anaerobic sequencing batch reactor: techno-economic assessment and kinetic modelling

Independent hydrogen production from petrochemical wastewater containing mono-ethylene glycol (MEG) via anaerobic sequencing batch reactor (ASBR) was extensively assessed under psychrophilic conditions (15–25 °C). A lab-scale ASBR was operated at pH of 5.50, and different organic loading rates (OLR) of 1.00, 1.67, 2.67, and 4.00 gCOD/L/d. The hydrogen yield (HY) progressed from 134.32 ± 10.79 to 189.09 ± 22.35 mL/gMEG_initial at increasing OLR from 1.00 to 4.00 gCOD/L/d. The maximum hydrogen content of 47.44 ± 3.60% was achieved at OLR of 4.0 gCOD/L/d, while methane content remained low (17.76 ± 1.27% at OLR of 1.0 gCOD/L/d). Kinetic studies using four different mathematical models were conducted to describe the ASBR performance. Furthermore, two batch-mode experiments were performed to optimize the nitrogen supplementation as a nutrient (C/N ratio), and assess the impact of salinity (as gNaCl/L) on hydrogen production. HY substantially dropped from 62.77 ± 4.09 to 6.02 ± 0.39 mL/gMEG_initial when C/N ratio was increased from 28.5 to 114.0. Besides, the results revealed that salinity up to 10.0 gNaCl/L has a relatively low inhibitory impact on hydrogen production. Eventually, the cost/benefit analysis showed that environmental and energy recovery revenues from ASBR were optimized at OLR of 4.0 gCOD/L/d (payback period of 7.13 yrs).     

Hydrocarbon-based electrode ionomer for proton exchange membrane fuel cells

The electrode ionomer is a key factor that significantly affects the catalyst layer morphology and fuel cell performance. Herein, sulfonated poly(arylene ether sulfone)-based electrode ionomers with polymers of various molecular weights and alcohol/water mixtures were prepared, and those comprising the alcohol/water mixture showed a higher performance than the ones prepared using higher boiling solvents, such as dimethylacetamide; this is owing to the formation of the uniformly dispersed ionomer catalyst layer. The relation between ionomer molecular weight for the same polymer structure and the sulfonation degree was investigated. Because the chain length of polymer varies with molecular weight and chain entanglement degree, its molecular weight affects the electrode morphology. As the ionomer covered the catalyst, the agglomerates formed were of different morphologies according to their molecular weight, which could be deduced indirectly through dynamic light scattering and scanning electron microscopy. Additionally, the fuel cell performance was confirmed in the current-voltage curve.     

The Interplay of Modulus,Strength, and Ductility in Adhesive Design Using Biomimetic Polymer Chemistry

High‐performance adhesives require mechanical properties tuned to demands of the surroundings. A mismatch in stiffness between substrate and adhesive leads to stress concentrations and fracture when the bonding is subjected to mechanical load. Balancing material strength versus ductility, as well as considering the relationship between adhesive modulus and substrate modulus, creates stronger joints. However, a detailed understanding of how these properties interplay is lacking. Here, a biomimetic terpolymer is altered systematically to identify regions of optimal bonding. Mechanical properties of these terpolymers are tailored by controlling the amount of a methyl methacrylate stiff monomer versus a similar monomer containing flexible poly(ethylene glycol) chains. Dopamine methacrylamide, the cross‐linking monomer, is a catechol moiety analogous to 3,4‐dihydroxyphenylalanine, a key component in the adhesive proteins of marine mussels. Bulk adhesion of this family of terpolymers is tested on metal and plastic substrates. Incorporating higher amounts of poly(ethylene glycol) into the terpolymer introduces flexibility and ductility. By taking a systematic approach to polymer design, the region in which material strength and ductility are balanced in relation to the substrate modulus is found, thereby yielding the most robust joints.     

Effect of hyperbranched poly(citric polyethylene glycol) with various polyethylene glycol chain lengths on starch plasticization and retrogradation

A series of hyperbranched poly(citric polyethylene glycol) (PCPEG) materials with varied polyethylene glycol (PEG) chain lengths as plasticizers were mixed with maize starch (MS) via cooking and film‐forming. The structure, pasting property, plasticization, aging property, moisture absorption and compatibility of plasticized starches were studied by means of Fourier transform infrared spectroscopy, X‐ray diffraction, rapid viscosity analysis, tension testing, moisture absorption measurements and scanning electron microscopy. Compared with PEG and citric acid, PCPEG was more effective in promoting starch chain movement and inhibiting the retrogradation of starch film. Also, PCPEG/MS had smaller moisture content. The longer the plasticizer chain, the better were the aging resistance and moisture resistance of starch. But with an increase of PEG chain length, mechanical properties of PCPEG/MS deteriorated and the compatibility between PCPEG and MS decreased. The hyperbranched derivative of PEG with longer chain exhibited improved plasticization and compatibility with starch. © 2019 Society of Chemical Industry     

Investigation on sulphonated zinc oxide nanorod incorporated sulphonated poly (1,4-phenylene ether ether sulfone) nanocomposite membranes for improved performance of microbial fuel cell

Hydrothermally prepared zinc oxide nanorods are sulphonated (S–ZnO NR) and incorporated into 15% Sulphonated Poly (1,4-Phenylene Ether Ether Sulfone) (SPEES) to improve the hydrophilicity, water uptake and ion transfer capacity. Water uptake and ion transfer capacity increased to 34.6 ± 0.6% and 2.0 ± 0.05 meq g^?1 from 29.8 ± 0.3% and 1.4 ± 0.04 meq g^?1 by adding 7.5 wt% S–ZnO NR to SPEES. Morphological studies show the prepared S–ZnO NR is well dispersed in the polymer matrix. SPEES +7.5 wt% S–ZnO NR membrane exhibits optimum performance after three-weeks of continual operation in a fabricated microbial fuel cell (MFC) to produce a maximum power density of 142 ± 1.2 mW m^?2 with a reduced biofilm compared to plain SPEES (59 ± 0.8 mW m^?2), unsulphonated filler incorporated SPEES (SPEES + 7.5 wt% ZnO, 68 ± 1.1 mW m^?2) and Nafion (130 ± 1.5 mW m^?2) thereby suggesting its suitability as a sustainable and improved cation exchange membrane (CEM) for MFCs.     

二氧化碳加氢直接合成二甲醚催化剂的研究——沉淀次序对复合催化剂结构和性能的影响

以草酸乙醇溶液为沉淀剂,采用不同的沉淀次序(并流、反加和正加)制备了CuO-ZnO-Al2O3/HZSM-5复合型催化剂,对CO2加氢直接合成二甲醚反应的催化活性顺序为:并流法催化剂>反加法催化剂>正加法催化剂。3种复合催化剂的还原温度由低到高的顺序为:并流法催化剂<反加法催化剂<正加法催化剂。在沉淀过程中,反加法和正加法均形成类胶体沉淀,相应催化剂的比表面积也较大。IR研究发现,催化剂在1101cm-1处表现Cu/Zn/Al氧化物与HZSM-5分子筛之间相互作用的IR吸收峰强度与其催化活性间存在对应关系。XRD结果表明,并流法得到的催化剂前驱体中有铜锌同形取代现象,有利于催化剂活性的发挥。     

Cu基络合物催化甲醇液相氧化羰化反应

针对甲醇液相氧化羰基化法合成碳酸二甲酯(DMC)工艺,开发了新型Cu基络合催化剂(CuB rnLm)。对CuB rnLm催化剂的活性及其稳定性进行了研究。实验结果表明,采用该催化剂,甲醇转化率和DMC选择性较高;元素价态和物质结构分析表明,CuB rnLm催化剂循环使用5次后仍保持较好的稳定性。采用正交设计和中心响应曲面法设计实验,并使用S tatistica软件进行统计分析,寻求出反应的主要影响因素,并得到优化的工艺条件:反应温度100~110℃、反应压力3.0~3.5M Pa、反应时间4~6h、CuB rnLm催化剂质量浓度(以甲醇的体积计)0.15~0.20g/mL。在此工艺条件下,甲醇转化率可达23%以上,DMC的选择性为96%~98%。     

癸二酸二甲酯与1,2,2,6,6-五甲基哌啶醇的酯交换反应

对癸二酸二甲酯与1,2,2,6,6-五甲基哌啶醇的酯交换反应进行了研究;分别考察了四异丙基钛酸酯、氨基锂、氧化二辛基锡3种催化剂的性能;采用氢核磁共振确定了产物的结构;考察了以四异丙基钛酸酯为催化剂时反应温度、反应时间、原料配比和催化剂用量对反应的影响。实验结果表明,四异丙基钛酸酯催化剂的催化效果最好;在癸二酸二甲酯与1,2,2,6,6-五甲基哌啶醇摩尔比1∶1.79、四异丙基钛酸酯催化剂的用量为反应物总质量的0.31%、反应温度180℃、反应时间6h的条件下,所得产物中单(1,2,2,6,6-五甲基-4-哌啶基)癸二酸甲酯(简称单酯)质量分数为23%和双(1,2,2,6,6-五甲基-4-哌啶基)癸二酸酯(简称双酯)质量分数为73%,单双酯质量比为1∶3.17,产物收率为93.3%。该方法可得到理想的单双酯比例及产物收率,具有很好的工业应用前景。