Experimental Design as a Tool for Optimizing and Predicting the Nanofiltration Performance by Treating Antibiotic-Containing Wastewater

Abstract

In recent years, there has been an increase in studies regarding nanofiltration-based processes for removing antibiotics and other pharmaceutical compounds from water and wastewater. In this work, a 2k factorial design with five control factors (antibiotic molecular weight and concentration, nanofiltration (NF) membrane, feed flow rate, and transmembrane pressure) was employed to optimize the NF performance on the treatment of antibiotic-containing wastewater. The resulting multiple linear regression model was used to predict the antibiotic rejections and permeate fluxes. Additional experiments, using the same membranes and the same antibiotics, but under different conditions of transmembrane pressure, feed flow rate, and antibiotic concentration regarding the 2k factorial design were carried out to validate the model developed. The model was also evaluated as a tertiary treatment of urban wastewater for removing sulfamethoxazole and norfloxacin. Considering all the conditions investigated, the tightest membrane (NF97) showed higher antibiotics rejection (>97%) and lower permeate fluxes. On the contrary, the loose NF270 membrane presented lower rejections to sulfamethoxazole, the smallest antibiotic, varying from 65% to 97%, and permeate fluxes that were about three-fold higher than the NF97 membrane. The good agreement between predicted and experimental values (R2 > 0.97) makes the model developed in the present work a tool to predict the NF performance when treating antibiotic-containing wastewater.

The Effect of pH on Atenolol/Nanofiltration Membranes Affinity

“…Over the last three decades, the occurrence of pharmaceutical compounds in the environment, as well as the different solutions aimed at removing these compounds from wastewater, thus preventing them from reaching the environment, have been the central theme of numerous scientific articles [1][2][3][4]. Among these solutions are treatments by advanced oxidative processes [5][6][7], membrane filtration technologies [8][9][10], biological processes [11][12][13], and combined processes [14,15].…”

Concentration with Nanofiltration of Red Wine Cabernet Sauvignon Produced from Conventionally and Ecologically Grown Grapes: Effect on Volatile Compounds and Chemical Composition

“…The pH of the feed influenced the membrane surface charge, permeate flux and retention of individual compounds. Polyamide membranes have an isoelectric point at pH 3.5–4.0, at which maximum permeate flux and the highest permeability occurred [ 53 ]. If the pH is higher than the isoelectric point, a negative charge increase will occur on the membrane surface increasing ion rejection [ 54 ].…”

Concentration with Nanofiltration of Red Wine Cabernet Sauvignon Produced from Conventionally and Ecologically Grown Grapes: Effect on Phenolic Compounds and Antioxidant Activity

“…If the pH is closer to the isoelectric point of a membrane, the retention of bioactive compounds will decrease [ 54 ]. The isoelectric point of polyamide membranes is usually at pH 3.5 to 4.0 [ 55 ], and the pH values of conventional and ecological wine used in this study were 3.92 and 3.75, respectively. Furthermore, Arsuaga et al [ 56 ] reported that the retention of the phenolic compounds depended on their adsorption on nanofiltration membranes.…”