超滤法与吸附法对茶饮料澄清作用的比较

将超滤法与吸附法对茶饮料的澄清作用进行了比较，证明不论是保留茶的有效成分还是澄清效果，二者均匀有显著差异（Ｐ〈０．０５或Ｐ〈０．００１），超滤法明显优于吸附法。     

COMPARATIVE LIMITING FLUX ANALYSIS OF BLACK LIQUOR AND POLYETHYLENE GLYCOL IN ULTRAFILTRATION

Ultrafiltration of black liquor was carried out using an asymmetric membrane and the results were compared with that of polyethylene glycol, a standard macromolecule, in a stirred batch cell. The effects of system parameters, e.g., pressure, concentration and stirrer speed on permeate flux and solute rejection were studied extensively for both the solutes.

An osmotic pressure model was used to analyze experimental results. To take into account the phenomena of concentration polarization, an extra resistance term, called the polarization layer resistance (R_p), was incorporated into the model. The polarization layer resistance was found to be a function of flow regime and concentration at the membrane. To correlate these, the following two types of relationship were examined and tested with the experimental results,

and

where a, b, c, a₁, b₁, are constants.     

A compact process for the treatment of olive mill wastewater by combining OF and UV/H2O2 techniques

Olive oil production results in important quantities of wastewater containing large amounts of total solids and organic carbon as well as low oil concentrations. This paper describes the treatment of olive mill wastewater (OMW) by combining an ultrafiltration (UF) technique and an advanced oxidation process (AOP) using UV/H₂O₂. It further demonstrates the technical feasibility of this compact and stable process to remove a large part of total solids and organic carbon. Indeed, OF reduces the pollutants contained in the OMW with an apparent rejection coefficient R_COD in the range of 94%. The UV/H₂O₂ oxidation process may be easily used, in combination with UF, to finish the treatment of the permeate. The results obtained in batch and continuous mode showed that this technique offered a treated solution which complies with legal requirements. A final concentration of 17 mg_TOC dm⁻³ was obtained, which corresponds to a final COD of 52 mg dm⁻³, while the legal requirement is 125. Furthermore, the final effluent is fully decolorized.     

固定化溶菌酶的氧化石墨烯/聚醚砜杂化超滤膜制备及抗菌性能研究

以氧化石墨烯(GO)为固定酶载体,在水溶液中通过静电吸附及氢键作用实现溶菌酶(Ly)的固定化得到GO-Ly。并将已固定化酶的GO为添加剂,以聚醚砜为膜材料,采用相转化法制备杂化超滤膜。考察了添加剂含量对膜形态、亲水性、分离性能、力学性能及抗菌性能的影响。结果表明,GO-Ly的加入使杂化膜的亲水性及纯水通量得到明显提高,同时拉伸强度也得到一定改善;尤其当GO-Ly添加量为1.5%(质量分数)时,膜的纯水通量达到318 L/(m2.h),并且对聚乙烯醇(PVA 30 000～70 000)的截留率维持在99%以上,对大肠杆菌的抑菌率可达68%。     

用于锅炉补给水处理的多级膜组合工艺及应用示范

超滤、纳滤、反渗透及EDI是实用性先进功能膜材料技术,高效节能,在锅炉补给水处理中应用潜力巨大。与目前所采用的单一膜工艺相比,多级膜组合处理工艺具有出水品质更高、无二次污染等明显优势。本研究以华纺股份有限公司的锅炉补给水系统工程系统为例,具体分析了超滤-反渗透-EDI多膜组合工艺、膜器系统及其在锅炉补给水处理中的效果。实际运行结果表明,该组合工艺能高效地去除水中盐类及小分子有机物,充分满足锅炉补给水的各项水质标准,而且具有运行周期长、出水水质稳定、连续出水等优点。     

Characterization of phospholipid reverse micelles in nonaqueous systems in relation to their rejection during membrane processing

The phospholipid (PL) rejection mechanism during membrane degumming was evaluated based on its critical micelle concentration (CMC) levels in undiluted and hexane-diluted vegetable oils. In this context, the influence of PL composition and solvent medium on the CMC levels has been investigated. In real and model systems, higher phosphatidylcholine to PL ratio lowered the CMC value and vice versa. The CMC of PL was lower in hexane-diluted systems when compared to undiluted oil systems owing to the greater hydrophobic-repulsive forces between hexane and amphiphilic PL. The PL rejection by UF membrane was near complete when the PL content of system was above CMC. Among the systems with lower PL contents (< CMC), rejection was greater in hexane-diluted systems (82-99% in lecithin-hexane system) than in undiluted oil systems (~ 40% in sunflower oil) owing to greater concentration polarization effect responsible for reverse micelle formation at the membrane surface leading to their subsequent rejection. UF membranes are generally preferred owing to higher productivity and the results suggest that their rejection performance could be kept high by careful manipulation of initial PL content. Nonporous membranes were effective in degumming vegetable oils irrespective of initial PL content and the type of system.     

撬式过滤组合在低温甲醇洗工艺中的应用探讨

气体净化中的低温甲醇洗工艺是近年来脱除酸性气体普遍采用的一种净化工艺。该工艺以其技术成熟、溶剂廉价易得、净化度高、选择性好等特性,被广泛应用于合成氨、合成醇类等行业。甲醇循环液的纯净度是保证低温甲醇洗装置的长周期稳定运行的重要前提。撬式过滤组合被应用于低温甲醇洗工艺,能有效确保甲醇液的洁净度。     

陶瓷多层选择膜工艺

综述了制取陶瓷微滤和超滤多层选择膜的6种工艺方法，并指出了膜层的结构特点。     

Critical flux in cross-flow ultrafiltration of protein solutions

The effect of solute size relative to membrane pore size on the critical flux during the ultrafiltration of protein solutions was investigated using the constant pressure method. Hydrophilic regenerated cellulose membranes with a cut-off of 10, 30 and 100 kg mol⁻¹, model proteins and skimmed milk solutions were used. The critical flux mainly increased with the pore size of the ultrafiltration membrane. The lowest critical fluxes, 40-50 L m⁻²h⁻¹, were obtained with the retentive 10 kg mol⁻¹ cut-off membrane. This membrane had a very low permeability and, thus, the critical fluxes were achieved at high transmembrane pressures (TMP): 1.7-2.3 bar. With the 100 kg mol⁻¹ cut-off membrane critical fluxes were obtained at 0.2 bar TMP, which were around 100 L m⁻² h⁻¹, slightly declining with increasing protein molar mass. In skimmed milk experiments the permeate flux decreased when the protein molecules were enzymatically split to peptides. A critical flux for skimmed milk solution could not be found unless the protein concentration was diluted to 0.3-w% or lower. The results with model proteins were then compared to those obtained with skimmed milk resulting in β-lactoglobulin being the worst foulant.