Mechanism of removal of pharmaceuticals and personal care products by nanofiltration membranes

Abstract

A B S T R A C TMuch attention has been paid to pharmaceuticals and personal care products (PPCPs). Nanofiltration (NF) is a new type of separation technology developed between ultrafiltration and reverse osmosis (RO) in the mid-1980s, which is a continuation and development branch of the ultra-low pressure RO technology. PPCPs are a kind of water ubiquitous trace organics, and there are some disadvantages of the PPCPs, such as recalcitrance, accumulation of biological toxicity and long-term dangers, which gradually attracts the attention of the scientific community due to the harm to the environment and ecosystems. This paper analyses the latest research progress in this country and overseas, introducing the advantages on removal of the PPCPs by NF membranes, also recommending the mechanism of the removal process and influencing factors. The direction of future research is proposed as well.

Rejection rate and mechanisms of drugs in drinking water by nanofiltration technology

“…Thereby, the pH value of the solution plays a significant role in removing charged drugs by NF. Some studies have reported that the role of electrostatic repulsion is very crucial in removing the charged organic solutes [20][21][22][27][28][29]. Based on our literature survey, the role of steric exclusion for removal the charged organic solutes is still not clear.…”

“…Recently, some researchers investigated the removal performance of drugs by NF technology [20][21][22][23][24][25]. Three major drug removal mechanisms are proposed, including steric exclusion, electrostatic repulsion and adsorption.…”

“…The molecular weight cut-off (MWCO) of NF and the molecular weight of drug are employed to evaluate the removal efficiency. However, it is inadequate and inaccurate to adopt the MWCO to evaluate the removal performance of NF as well as use the molar weight to weigh the size of drug molecule [20]. In addition, increasing environmental awareness coupled with more stringent regulation standards has triggered various industries to challenge themselves in seeking appropriate wastewater treatment technologies [21].…”

“…The amount of negative charges on membrane surface increases with the increase of the pH value of the solution due to the acid group on membrane surface is gradually dissociated. Thus, the amount of negative charges on membrane surface would be changed with the pH value of the solution [20][21][22][23][28][29]. Note that drugs containing acid functional groups (e.g., the carboxylic group, phenolic hydroxyl group and et al) have several different forms based on the pH value of feed solution.…”

Preparation of Cross-Linked Graphene Oxide on Polyethersulfone Membrane for Pharmaceuticals and Personal Care Products Removal

“…As an alternative technology, the use of membranes has attracted attention due to its wide range of removal, low energy consumption, compact equipment, and simple operation [ 12 , 13 ]. One of the membrane separation processes, nanofiltration (NF) is a good means of removing PPCPs [ 14 , 15 ]. However, in practical applications, the traditional NF membrane does not simultaneously provide good chemical stability, microbial resistance, and high mechanical strength.…”