Characteristics of meso-particles formed in coagulation process causing irreversible membrane fouling in the coagulation-microfiltration water treatment

Abstract

In coagulation-membrane filtration water treatment processes, it is still difficult to determine the optimal coagulation condition to minimize irreversible membrane fouling. In microfiltration (MF), meso-particles (i.e., 20 nm-0.5 μm) are thought to play an important role in irreversible membrane fouling, especially their characteristics of particle number (PN) and zeta potential (ZP). In this study, a new nanoparticle tracker combined a high-output violet laser with a microscope was developed to identify the physicochemical characteristics of these microscopic and widely dispersed meso-particles. The effects of pH and coagulant dose on ZP and PN of micro-particles (i.e., >0.5 μm) and meso-particles were investigated, and then coagulation-MF tests were conducted. As the result, irreversible membrane fouling was best controlled for both types of membranes, while meso-particle ZP approached zero at around pH 5.5 for both types of natural water. Since PN was greatest under these conditions, ZP is more important in determining the extent of irreversible membrane fouling than PN. However, the acidic condition to neutralize meso-particles is not suitable for actual operation, as considering residual aluminum concentration, pipe corrosion, and chlorination efficiency. It is therefore necessary to investigate coagulants or other methods for the appropriate modification of meso-particle characteristics.

The Effect of Wastewater Treatment Plants on Retainment of Plastic Microparticles to Enhance Water Quality—A Review

“…It was seen that mesoparticles (i.e., 20 μm -0.5 μm, falling within the size of many microplastics) can play a role in irreversible membrane fouling and that a prior coagulation process is of utmost importance [208]. An alternative membrane separation technology is that using dynamic membranes (DMs).…”

Interpenetrating network nanoarchitectonics of antifouling poly(vinylidene fluoride) membranes for oil–water separation

“…Compared with PVDF membrane surface, the m-PVDF-2 membrane surface has a higher positive charge, which may be related to the graed neutral PEG polymer. 34 The reason for this decrease is that PEG is a neutral charge polymer, and the neutral charge coating hinders the protonation of amines and a The error in contact angle measurement is no more than 1 . the decomposition of phenolic hydroxyl groups to a certain extent.…”

The Effect of Wastewater Treatment Methods on the Retainment of Plastic Microparticles

“…UF can also be used as a pretreatment for a reverse osmosis (RO) separation (see below) to protect the RO membrane. Nevertheless, fouling of membranes due to meso-particles, where MP have the same size, continues to be a problem [150].…”