The role of adsorption on nanofiltration of azo dyes

Abstract

The influence of osmotic pressure and solute adsorption on permeate flux during nanofiltration (NF) of a wool textile dye solution was investigated. Solutions of C.I. Acid Orange 7 with concentrations ranging from 2 to 2000 mg/l were subjected to nanofiltration with a NF 45 membrane. An increase of flux decline with dye concentration was observed. The resistance-in-series model gives evidence that the main factor causing this flux decline is the solute adsorption. This is reinforced by the increase in the apparent rejection with dye concentration. Although osmotic pressure was taken into account, its contribution to a decrease of the driving force seems not to be significant. Adsorption resistance was calculated from a correlation between the pure water fluxes, measured before and after the essays, and feed dye concentration. A Langmuir isotherm type curve agreed well with experimental data. From the solution-diffusion model, the intrinsic rejection coefficient can be predicted as function of feed dye concentration.

Facile synthesis and characterization of Fe3O4 nanopowder and Fe3O4/reduced graphene oxide nanocomposite for methyl blue adsorption: A comparative study

“…Fe 3 O 4 nanoparticles have been most 11 widely studied in different areas among all magnetic nanoparticles 12 due to its low toxicity to the human health and environment 13 friendly and it also shows super paramagnetic behavior [2]. Due to 14 these properties, it has wide applications in the biological and 15 medical fields such as enzyme and protein immobilization, 16 magnetic resonance imaging (MRI), radiopharmaceuticals, diag- 17 nostics, RNA and DNA purification, immunoassays, magnetic cell 18 separation and purification, magnetically controlled transport of 19 anti-cancer drugs, etc.…”

“…Removal of dye molecule from aqueous 52 system is an important study as dyes are one of the major water 53 pollutants. such as textile, paper, printing, cosmetics, food, pharmaceuticals, 57 fabric and so on [12,13]. Release of dye containing wastewater from 58 these industries to main water stream is a serious challenge to the 59 aquatic flora and fauna as well as to the whole environment.…”

“…60 Therefore, treatment of the dye containing wastewater before 61 surface discharge is extremely important. A number of methods 62 such as membrane filtration, trickling filter, active sludge, chemical 63 coagulation, adsorption etc., have been reported for removal of dye 64 molecules from water system [12,13]. Adsorption is considered to 65 be the most suitable and favorable method in this regards due to its 66 simplicity and cost effectiveness [14].…”

An effective removal of methylene blue dye using polyacrylonitrile yarn waste/graphene oxide nanofibrous composite

“…Many methods such as chemical coagulation, photo degradation, membrane filtration, and adsorption have been studied conventionally for dye removal purpose (Gomes et al 2005;Sivakumar and Palanisamy 2009). Though a number of techniques are available for dye removal from aqueous solutions, adsorption is one of the most efficient techniques used worldwide due to the high adsorption capacity, cost effectiveness, and simple handling process (Dubey et al 2009;Christian Kemp et al 2013;Linjun et al 2013).…”

Box behnken design based optimization of solar induced photo catalytic decolourization of textile dye effluent

“…These include adsorption using activated carbon [8,9], coagulation [10,11], flocculation [12] membrane filtration [13], nano filtration [14,15] and chemical processes like electro chemical oxidation [16][17][18], Fenton reactions [19], ozonation [20] sonochemical [21] and biological processes [22][23][24][25][26][27].…”