氧化破胶-絮凝过滤工艺降黏处理压裂返排液的研究

针对压裂返排液黏度较大、有机污染物含量高和处理难度大的特点,采用以Fenton试剂为氧化剂,聚合氯化铝为絮凝剂的氧化破胶-絮凝过滤工艺对其进行降黏处理和回收利用,并以黏度为指标,考察了Fenton试剂中H_2O_2(30%)、FeSO_4(0.5 mol·L~(-1))添加量及溶液pH、氧化破胶反应时间、絮凝剂种类和用量对降黏效果的影响。结果表明,对于100 mL黏度为16 m Pa·s的油田压裂返排液,当溶液pH为3.0,Fenton试剂中H_2O_2和FeSO_4添加量分别为0.48 mL和0.3 mL,反应时间为50 min时,氧化破胶效果最佳;氧化破胶后的溶液再经0.5 g聚合氯化铝絮凝过滤处理后,黏度可以降至1.1 m Pa·s,溶液中的大部分污染物也被除去,可以实现循环回收利用。     

Surface sedimentation and adherence of Nano‐SiO2 to improve thermal stability and flame resistance of melamine‐formaldehyde foam via sol‐gel method

Melamine‐formaldehyde foam possesses intrinsic flame retardance; however, relative poor thermal stability and a certain amount of heat release rate restrict its applications in heated environment to a degree. In the present research, sol‐gel method has been adopted to precipitate nano‐SiO₂ particles on the surface of the melamine‐formaldehyde foam's fibers to construct a protective inorganic gel layer. Taking advantages of the shielding effects of the gel layer, the thermal‐oxygen degradation of the foam can be greatly retarded during heating; hence, the thermal stability is remarkably improved, and the flame retardance is further enhanced. In addition, introducing a small amount of membrane‐forming agent in the sol‐gel system can make the depositional nano‐SiO₂ particles well adhered to avoid dusting.     

滴定-凝胶法制备球形水凝胶吸附材料及其在废水处理中的应用

滴定-凝胶法制备球形水凝胶吸附材料具有3D倒漏斗状微观形貌结构，孔径分布宽泛，对水体中重金属、染料等污染物具有快速响应机制，已被广泛用于水处理过程研究。综述了滴制法制备球形水凝胶吸附材料的主要过程机理、水凝胶具有的特殊形貌结构及其在水处理过程中的应用，分析了球形水凝胶吸附材料在水处理应用过程中存在的问题和局限，并指出了其在水处理领域的应用前景及发展方向。     

巴彦河套盆地片麻岩储层改造工艺研究及应用

巴彦河套片麻岩储层具有埋藏浅、低温、低孔低渗透、天然裂缝发育、孔喉连通性差、非均质性强等特征,储层改造过程中存在加砂困难、缝高失控、压裂液难以破胶等风险,根据上述难点,结合岩石力学分析和非常规储层压裂理论,形成了水力裂缝沟通天然裂缝、多裂缝延伸形成缝网,增渗增产的储层改造工艺技术,同时配套多尺度裂缝支撑、缝高控制及低温破胶技术。该技术在巴彦河套盆地片麻岩裂缝储层的3口井已得到成功应用,压后产油量10.50～27.96m3/d,平均产油量达到19.83m3/d,对巴彦河套盆地片麻岩裂缝储层后期勘探开发具有重要的借鉴意义。     

Characterization of the structure and diffusion behavior of calcium alginate gel beads

A simple and novel method using gel shrinkage to indirectly characterize the structure of calcium alginate gel (CAG) beads during the calcium alginate gelation process was presented in this study. The effect of preparation process parameters (gelling cations, bead diameter, and alginate M _w and concentration) on the structure of the CAG bead formation process was thoroughly investigated. It was found that (a) the concentration of the Na⁺ and Ca²⁺ ion in gel bath was found to be the determining factor in the gel structure formation process by regulating the dissociation of alginate and the complexation of the calcium; (b) Na⁺ acts as a competitor with calcium and a screen in the electrostatic repulsion; (c) the effect of beads size below 700 μm on the structure of CAG beads can be neglected; and (d) the sodium alginate concentration has no significant effect on the gel formation process. Furthermore, the diffusion of bovine serum albumin (BSA) was controlled by the density of CAG bead. Consequently, a faster diffusion rate of BSA within the looser structure of beads can be observed. These results are keys to understanding the behavior and performance of beads in their utilization medium. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48923.     

Effects of size and autoclavation of fruit and vegetable wastes on biohydrogen production by dark dry anaerobic fermentation under mesophilic condition

Fermentative hydrogen production from fruit and vegetable wastes (FVWs) through Dry Fermentation Technology (DFT) was studied through three independent experiments in order to find out the effect of particle size and autoclaving pretreatment on bio-hydrogen production from FVWs and as follows: (1) autoclaved FVWs with sizes < 5 cm (experiment I); (2) raw FVWs with sizes < 5 cm (experiment II) and (3) autoclaved FVWs with sizes > 5 cm (experiment III). The assay with autoclaved waste yielded a higher percentage of hydrogen in the headspace of the dry fermenter reaching a maximum value of 44% in experiment I. However, the maximum hydrogen production was obtained in experiment III with 14573 NmL at a yield of 23.53 NmL H₂/gVS. Profiling of the microbial communities by denaturing gradient gel electrophoresis (DGGE) indicated that the most prominent species were the genera Clostridium, Bifidobacterium, and Lactobacillus.     

Toward a continuous synthesis of porous carbon xerogel beads

A continuous process for producing porous carbon xerogel beads has been developed. It consists in injecting a pre‐cured aqueous solution of resorcinol and formaldehyde on top of a column filled with hot oleic acid. The latter is pumped on the top of the column and fed at the bottom, generating an upward flow that can be adjusted to match the terminal velocity of the settling beads. Thus, the bead residence time in the column can be adjusted to match the gelation time, allowing the beads to solidify before reaching the bottom of the vessel. The obtained beads are subsequently dried and pyrolyzed. The developed experimental setup proved the continuous synthesis of porous carbon beads is possible. Nevertheless, the shaping process caused various texture changes of the porous carbon, which mainly yields macropores instead of micro and mesopores. This process also leads to the build‐up of a denser skin around the beads. © 2018 American Institute of Chemical Engineers AIChE J, 64: 1049–1058, 2018     

Enhancement of glass-ceramic performance by TiO2 doping: In vitro cell viability,proliferation, and differentiation

A new TiO₂-containing bioactive glass and glass-ceramics based on 50SiO₂-(45-X)CaO-(XTiO₂)-5P₂O₅ system was designed using a sol–gel technique (where X = 5, 7.5 and 10 wt %). The roles of the crystallization behavior and physicochemical characteristics of the designed glass and glass-ceramics which were played in the introduction of TiO₂ substitutions were investigated. Moreover, cell proliferation and differentiation were evaluated against human osteosarcoma cells (Saos-2). The TiO₂/CaO replacements led to the formation of a stronger glass structure and thus increased thermal parameters and the chemical stabilization of the designed materials. The FTIR data confirmed the existence of Ti within the glass and glass-ceramics samples, and no remarkable effect on their chemical integrity was observed. The XRD patterns indicated that calcium-containing minerals, including Ca₂SiO₄,Ca₃(PO₄)₂, Ca(Ti,Si)O₅, CaTiSiO₅, and Ca₁₅(PO₄)₂·(SiO₄)₆ phases were developed as a role of structure/texture under the applied heat-treatment. The results of the cytotoxicity test proved that a safe sample dose is 12–50 μg/ml, at which cell viability is ≥ 85%. The cell differentiation determined by ALP test proved the superiority of glass-ceramics compared with their native glasses. Therefore, the obtained materials could be safely used as novel biocompatible materials for the regeneration of bone tissue.     

3D CaP porous scaffolds with grooved surface topography obtained by the sol-gel method

The influence of surface topography on cellular behaviour and its importance for the development of three-dimensional scaffolds for bone tissue engineering are a topic of growing interest. To date, the introduction of topographical patterns into the surface of 3D porous ceramic scaffolds has proven difficult, due partly to the brittle nature of ceramic materials as well as the currently available fabrication technologies. In this study, a grooved pattern was introduced into the surface of 3D multilayer porous ceramic scaffolds by the chemical etching technique. The patterned scaffolds were characterised by X-Ray Diffraction (XRD), Scanning Electron Microscopy with Energy Dispersive X-Ray Spectroscopy (SEM-EDX) and Digital Holographic Microscopy (DHM). Their bioactivity was also evaluated in vitro by immersion in simulated body fluid (SBF) for 12 h, 1, 7, 14 and 21 days. Scaffolds were constituted mainly with a mixture of the calcium pyrophosphate (Ca₂O₇P₂) and β-tricalcium phosphate (Ca?(PO?)?) phases. The pyrophosphate on the external layer was dissolved as a result of the etching process, leaving grooves on the surface. Ridges and grooves were nano-/micrometric, with dimensions of around 900 nm–1.5 μm in width and 200 nm–300 nm in depth. Moreover, the mechanical properties and bioactive capacity of the patterned scaffolds were not affected by chemical etching, making them suitable to be used in bone tissue engineering.