PVA modified filled copolymer membranes for pervaporative dehydration of acetic acid-systematic optimization of synthesis and process parameters with response surface methodology

A LDH Template Triggers the Formation of a Highly Compact MIL-53 Metal-Organic Framework Membrane for Acid Upgrading

Highly compact metal-organic framework (MOF) membranes offer hope for the ambition to cope with challenging separation scenarios with industrial implications. A continuous layer of layered double hydroxide (LDH) nanoflakes on an alumina support as a template triggered a chemical self-conversion to a MIL-53 membrane, with approximately 8 hexagonal lattices (LDH) traded for 1 orthorhombic lattice (MIL-53). With the sacrifice of the template, the availability of Al nutrients from the alumina support was dynamically regulated, which resulted in synergy for producing membranes with highly compact architecture. The membrane can realize nearly complete dewatering from formic acid and acetic acid solutions, respectively, and maintain stability in a continuous pervaporation over 200 h. This is the first success in directly applying a pure MOF membrane to such a corrosive chemical environment (lowest pH value of 0.81). The energy consumption is saved by up to 77 % when compared with the traditional distillation.

Recovery of cutting oil from wastewater by pervaporation process using natural clay modified PVA membrane

In this study, the pervaporative dehydration of the cutting oil 'diethylene glycol' (DEG) through a hydrophilic PVA membrane was investigated at various operation temperatures in the range of 333-363 K with a feed mixture containing 0.5-2.0 wt% water. The pervaporation (PV) performance of poly(vinyl alcohol) (PVA) is enhanced by the addition of natural clay kaolin into the pristine membrane. The thermal stability of the membranes was analyzed by thermal gravimetric analysis (TGA). The morphological analysis of the membranes was performed by scanning electron microscope (SEM). Separation success was determined by calculation of flux, selectivity, and PSI. These values were investigated as functions of the clay amount, feed concentration and feed temperature. The obtained results show that PV is an effective method for recycling waste cutting oil from wastewater.