Rudolph Gregor, Schagerlöf Herje, Morkeberg Krogh Kristian B, Jönsson Ann-Sofi, Lipnizki Frank
Department of Chemical Engineering, Lund University, Naturvetarvägen 14, Box 124, 22100 Lund, Sweden.
Novozymes A/S, Krogshoejvej 36, 2880 Bagsvaerd, Denmark.
Membranes (Basel). 2018 Oct 10;8(4):91. doi: 10.3390/membranes8040091.
The pulp and paper industry is one of the most important industrial sectors worldwide, and has considerable potential for the sustainable fractionation of lignocellulosic biomass to provide valuable compounds. Ultrafiltration (UF) is a suitable separation technique for the profitable production of hemicelluloses from process water from thermomechanical pulping (ThMP), but is limited by membrane fouling. Improvements in cleaning protocols and new alternative cleaning agents are required to ensure a long membrane lifetime, and thus a sustainable process. This study, therefore, focuses on the cleaning of polymeric UF membranes after the filtration of ThMP process water, comparing alkaline with enzymatic cleaning agents. The aim was to develop a cleaning procedure that is efficient under mild conditions, resulting in a lower environmental impact. It was not possible to restore the initial permeability of the membrane when cleaning the membrane with enzymes alone, but the permeability was restored when using a two-step cleaning process with enzymes in the first step and an alkaline cleaning agent in the second step. Scanning electron microscopy gave a deeper inside into the cleaning efficiency. Attenuated total reflectance Fourier-transform infrared spectroscopy analysis confirmed that not only polysaccharides, but also extractives are adsorbed onto the membrane surface.
制浆造纸工业是全球最重要的工业部门之一，在木质纤维素生物质可持续分级以提供有价值化合物方面具有相当大的潜力。超滤（UF）是一种从热机械制浆（ThMP）工艺水中盈利生产半纤维素的合适分离技术，但受膜污染限制。需要改进清洗方案和新型替代清洗剂以确保膜的长使用寿命，从而实现可持续工艺。因此，本研究聚焦于ThMP工艺水过滤后聚合物超滤膜的清洗，比较碱性清洗剂和酶清洗剂。目的是开发一种在温和条件下高效且对环境影响较小的清洗程序。单独用酶清洗膜时无法恢复膜的初始渗透率，但采用第一步用酶、第二步用碱性清洗剂的两步清洗工艺时渗透率得以恢复。扫描电子显微镜更深入地揭示了清洗效率。衰减全反射傅里叶变换红外光谱分析证实，不仅多糖，而且提取物也吸附在膜表面。
