Modeling of the retention of atrazine and dimethoate with nanofiltration

Ahmad, A.L.; Tan, Lian See; Shukor, Syamsul Rizal Abd

doi:10.1016/j.cej.2008.07.015

Cited by 15 publications

(9 citation statements)

References 22 publications

(35 reference statements)

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“…(19) we finally obtain a value for A=0.0241. This value is close to 0.0224 obtained by Ahmad et al [67], and both are in the interval given by Ahmad and Schäfer's [49].…”

Section: Retention Resultssupporting

confidence: 66%

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Pore size analysis from retention of neutral solutes through nanofiltration membranes. The contribution of concentration–polarization

et al. 2014

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Pore size distribution is one of the most important characteristics of a membrane.This can be obtained from the fitting of pore radius calculated from retention versus flux measurements for a set of solute solutions. In this work a set of non-charged similar molecules are chosen as solutes to minimize other interactions apart of those related to size. The hydrodynamic model will be used to characterize the behavior of the membrane to uncharged solutes, assuming that membrane pores are straight and cylindrical.As is known, the phenomenon of concentration polarization must be taken into account because true retention is not experimentally accessible by concentration measurements. Frequently, the film layer model is applied for the dependence of

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“…(19) we finally obtain a value for A=0.0241. This value is close to 0.0224 obtained by Ahmad et al [67], and both are in the interval given by Ahmad and Schäfer's [49].…”

Section: Retention Resultssupporting

confidence: 66%

“…These parameters are in concordance with experiment conditions, nonturbulent regime, as Re<30000 (stirring speed up to 400 rpm). The second, and the only using turbulent conditions, is from Ahmad et al [67]. Using the same Sterlitech cell they apply the equation proposed in Schäfer's book [49] for the mass transfer coefficient.…”

Section: Reynolds Numbermentioning

confidence: 99%

Pore size analysis from retention of neutral solutes through nanofiltration membranes. The contribution of concentration–polarization

et al. 2014

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“…In the NF process, solute rejection results in a concentration polarization at the membrane and bulk solution interface. Therefore, relationship between C m and C p in concentration polarization is expressed in the Film Theory Model [11,23] as:…”

Section: Theoretical Background and Calculation Methodsmentioning

confidence: 99%

The effects of feed solution temperature on pore size and trace organic contaminant rejection by the nanofiltration membrane NF270

Dang

Price

Nghiem

2014

Separation and Purification Technology

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“…It is of great importance to control DMT residue in waters for minimizing its risks to human beings. Many methods have been attempted for removing DMT from water, such as nanofiltration (Ahmad et al, 2009), ultrasonication (Liu et al, 2008;Yao et al, 2011), microwave irradiation (Zhang et al, 2007), photo-Fenton oxidation (Evgenidou et al, 2007;Martín et al, 2008Martín et al, , 2009, and biological oxidation (Martín et al, 2008(Martín et al, , 2009). However, toxic byproducts, such as omethoate (OMT), were formed during DMT oxidation.…”

Section: Introductionmentioning

confidence: 99%

Kinetics and mechanism of dimethoate chlorination during drinking water treatment

et al. 2014

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h i g h l i g h t sThe reaction of DMT with chlorine was of first-order in each reactant. The observed rate constant of DMT degradation was strongly pH dependent. Both bromide and humic acid promoted but ammonium inhibited the degradation of DMT. Three organic byproducts were detected in DMT degradation by chlorine. The toxicity of DMT solution obviously increased after chlorination. a r t i c l e i n f o a b s t r a c t Dimethoate (DMT), a commonly used organophosphorus pesticide, is of great concern because of its toxicity and potentially harmful effects on water sources. The elimination of DMT as well as the toxicity and persistence of the byproducts formed during DMT degradation is most important for the safety of drinking water. This study first determined the reaction kinetics of DMT with free chlorine (FC) under typical water treatment conditions. The reaction between DMT and FC proceeded rapidly, exhibiting first-order with respect to each reactant. The degradation of DMT by FC was highly pH dependent, and the pseudofirst-order rate constant decreased obviously from 0.13 to 0.02 s À1 with an increase in pH from 7.0 to 8.3. Bromide ion accelerated the reaction by acting as a catalyst, and the accelerated reaction rate was linearly proportional to the bromide concentration. As a ubiquitous component in natural waters, humic acid also increased the reaction rate. However, the presence of ammonium inhibited the degradation of DMT due to its rapid converting FC to chloramines. Omethoate (OMT) was identified as an important byproduct of DMT chlorination, but only accounted for ca. 28% of the DMT degraded; and other two organic byproducts were also identified. The acute toxicity of DMT solution increased after treatment with FC due to the formation of more toxic byproducts (e.g. OMT).

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Modeling of the retention of atrazine and dimethoate with nanofiltration

Cited by 15 publications

References 22 publications

Pore size analysis from retention of neutral solutes through nanofiltration membranes. The contribution of concentration–polarization

Pore size analysis from retention of neutral solutes through nanofiltration membranes. The contribution of concentration–polarization

The effects of feed solution temperature on pore size and trace organic contaminant rejection by the nanofiltration membrane NF270

Kinetics and mechanism of dimethoate chlorination during drinking water treatment

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