Atrazine removal from aqueous solutions by nanofiltration

Abstract

There is an increasing concern about the release of herbicides and other organic compounds to the environment as a result of agricultural activities, due to their high toxicity for living organisms and their difficult to be degraded. Triazines are widely used herbicides that are highly toxic and frequently appear in natural watercourses, atrazine being one of the most commonly detected herbicides in aquatic systems. The atrazine rejection coefficients and the permeate fluxes of different nanofiltration membranes (NF-99, NF-97, Desal-5-DL and Desal-5-DK) for the removal of atrazine from water solutions in different operating conditions (feed atrazine concentration, pressure and pH) are studied in this article. Atrazine rejection was greater with the NF 99 and NF 97 membranes (90-98%), while the DL and DK membranes show much lower rejections (40-50%). The highest permeate fluxes are obtained with NF-99 and DL membranes. Atrazine rejection and permeate flux show no dependence on the atrazine feed concentration, low dependence on pH and a high positive dependence on pressure (especially the permeate flux). The results are explained by taking into account different solute parameters and membrane properties that affect the nanofiltration process.

Application of the solution-diffusion model for the removal of atrazine using a nanofiltration membrane

“…In a previous paper [23], several experiments were carried out to study the influence of pressure, atrazine feed concentration and pH on atrazine rejection and solvent flux. Table 3 summarizes all the experimental conditions tested.…”

“…In a previous work [23], atrazine removal was studied using four different nanofiltration membranes, two of them were made of polyamide (NF-99 and NF-97) and the other two were made of polypiperazineamide (DL and DK). As a next step, in this work, the solution-diffusion model is applied to the experimental data obtained in the above-mentioned work to test the extent to which the model predicts the behaviour of the four different nanofiltration membranes used for atrazine removal.…”

Degradation of Atrazine by UV/PMS in Phosphate Buffer

“…7, Cland HCO 3 both had inhibitory effects on the degradation of ATZ in the system at the same concentration, mainly because Cland HCO 3 could compete with ATZ for HO• and SO 4 -• in the UV/PMS system to generate Cl•, Cl 2 -•, ClOH -• and CO 3 -•, whose reaction rates were lower than those of HO• and SO 4 -•. It is easy to observe that the inhibiting effect of Clwas higher than HCO 3 -, and specific performances were as follows: the degradation efficiency of ATZ was reduced from 77.40% to 41.14% and 63.58% respectively after adding 2 mmol/L of Cland HCO 3 to the UV/PMS system. This is mainly because the secondary reaction constants of Cl 2 -• and ATZ were lower than those of CO 3 -• and ATZ (the main equation is shown in formula 1-6 to 1-13).…”

Behaviour of RO90 membrane on the removal of 4-nitrophenol and 4-nitroaniline by low pressure reverse osmosis

“…Among them, membrane processes are suitable for removing organic pollutants from wastewater [18,19]. The molecular size of phenolic compounds and its derivatives make them possible candidates to be removed with reverse osmosis (RO) and nanofiltration (NF) pressure driven membrane processes [20][21]. 4-Nitrophenol removal has been studied with reverse osmosis [22], nanofiltration [23] and liquid membranes [24].…”