The removal of acrylonitrile from aqueous solution by Fenton's reagent and membrane filtration

2000 ◽  
Vol 41 (10-11) ◽  
pp. 143-148 ◽  
Author(s):  
C.Y. Chang ◽  
S.H. Chen ◽  
J.S. Chang ◽  
C.C. Wang

The removal of acrylonitrile by Fenton-precipitation and Fenton-microfiltration was investigated in this study. As for Fenton-precipitation, in the range of pH 2 to pH 4, TOC removal efficiency decreased with the increase in pH during the Fenton-precipitation of acrylonitrile. Fenton-microfiltration had a significant improvement on TOC removal at pH 3 and 4 as compared with Fenton-precipitation. The highest removal efficiency of 95% was obtained at pH 3 and the solution pH value had a significant effect on the total permeate quantity and the rate of accumulation. Experimental results led to the conclusion that the oxidation caused by Fenton's reagent was predominant at pH 2. On the contrary, coagulation was most significant at pH 3 and 4. The results indicated the superiority of the Fenton-microfiltration process as compared with Fenton-precipitation process for the removal of acrylonitrile from water.

2019 ◽  
Vol 84 (7) ◽  
pp. 713-727 ◽  
Author(s):  
Jiteng Wan ◽  
Chunji Jin ◽  
Banghai Liu ◽  
Zonglian She ◽  
Mengchun Gao ◽  
...  

Even in a trace amounts, the presence of antibiotics in aqueous solution is getting more and more attention. Accordingly, appropriate technologies are needed to efficiently remove these compounds from aqueous environments. In this study, we have examined the electrochemical oxidation (EO) of sulfamethoxazole (SMX) on a Co modified PbO2 electrode. The process of EO of SMX in aqueous solution followed the pseudo-first-order kinetics, and the removal efficiency of SMX reached the maximum value of 95.1 % within 60 min. The effects of major factors on SMX oxidation kinetics were studied in detail by single-factor experiments, namely current density (1?20 mA cm-2), solution pH value (2?10), initial concentration of SMX (10?500 mg L-1) and concentration of electrolytes (0.05?0.4 mol L-1). An artificial neural network (ANN) model was used to simulate this EO process. Based on the obtained model, particle swarm optimization (PSO) was used to optimize the operating parameters. The maximum removal efficiency of SMX was obtained at the optimized conditions (e.g., current density of 12.37 mA cm-2, initial pH value of 4.78, initial SMX concentration of 74.45 mg L-1, electrolyte concentration of 0.24 mol L-1 and electrolysis time of 51.49 min). The validation results indicated that this method can ideally be used to optimize the related parameters and predict the anticipated results with acceptable accuracy.


2011 ◽  
Vol 233-235 ◽  
pp. 737-740 ◽  
Author(s):  
Xiao Xia Ou ◽  
Chong Wang ◽  
Yan Su ◽  
Feng Jie Zhang ◽  
Guo Jiao Yang ◽  
...  

The degradation of rhodamine B (RB) in aqueous solution by Fenton’s reagent was studied. After 30 min, the 96.2% removal of RB in water (pH = 3.0, T = 25 °C) was achieved when the initial concentrations of Fe2+, H2O2 and RB were 0.5 mM, 5 mM and 10 mg/L, respectively. A higher initial concentration of Fe2+ and H2O2 resulted in a higher efficiency in RB discolorization. The removal of RB was dependent strongly on the pH value of solution. Increasing the reaction temperature was beneficial for the RB degradation. Based on the Arrhenius equation, the activation energy (Ea) was calculated to be 16.78 kJ/mol from rate constants at different temperatures. The degradation of RB by Fenton’s reagent was inhibited by the presence of oxalic acid.


2003 ◽  
Vol 47 (1) ◽  
pp. 41-48 ◽  
Author(s):  
J. Duan ◽  
N.J.D. Graham ◽  
F. Wilson

The coagulation of a model seawater-humic acid solution with a hydrolysis metal salt (FeCl3) has been studied by monitoring floc size, solution pH, and zeta potential. The kinetic features of the orthokinetic coagulation have been demonstrated in relation to coagulant dosages, solution pH and zeta potential. Humic acid removal and floc charge reduction increased with coagulant dosage. Adjusting the solution pH prior to coagulation had a substantial effect on the treatment performance. By pH adjustment to pH 6, the greatest humic acid removal (by coagulation and subsequent membrane filtration) and the largest floc size was achieved at a FeCl3 dosage of 200 mmol l−1. It is believed that the coagulation is characterised by competition between OH- ions and humic acid for ferric ions in the co-precipitation process. In acidic pH, where the concentration of OH- ions is low, humic acid molecules may compete more favourably for bonding sites in the co-precipitation, which leads to a more compact precipitation and a higher overall humic acid removal.


1996 ◽  
Vol 13 (6) ◽  
pp. 527-536 ◽  
Author(s):  
L.J. Alemany ◽  
M.C. Jiménez ◽  
M.A. Larrubia ◽  
F. Delgado ◽  
J.M. Blasco

The present work examines the possible use of fly ash, a byproduct of coal power stations, as a means of removing phenol from water, or equivalently, of restricting its movement in solid wastes or soil. Equilibrium experiments were performed to evaluate the removal efficiency of fly ash. The adsorption experiments were undertaken using fly ash treated at three different pH levels and with three different temperatures. The results indicate that although phenol can be removed from water, this depends markedly on the temperature and pH value of the treatment solution employed.


2009 ◽  
Vol 56 (6) ◽  
pp. 1147-1155 ◽  
Author(s):  
Chiing-Chang Chen ◽  
Ren-Jang Wu ◽  
Yi-You Tzeng ◽  
Chung-Shin Lu

2013 ◽  
Vol 545 ◽  
pp. 101-108 ◽  
Author(s):  
Kitirote Wantala ◽  
Nusavadee Pojananukij ◽  
Pongsert Sriprom ◽  
Tinnakorn Kumsaen ◽  
Arthit Neramittagapong ◽  
...  

Adsorption of Zn(II) and Pb(II) from aqueous solution were studied by using modified coir pith as an adsorbent. The extended adsorption conditions were investigated as a function of calcination temperature, contact time, adsorbent size, initial pH of solution and initial Zn(II) and Pb(II) concentrations. The adsorption capacity increased rapidly in first 5 minute and reached equilibrium in 120 minutes for Zn(II) and 10 minutes for Pb(II). In case of Zn(II); the results showed that the calcination temperature of modified coir pith above 600oC gave the higher adsorption capacity. The sizes of modified coir pith have no effect on the adsorption capacity. The adsorption capacity increased with increasing initial solution pH value. In case of Pb(II); the calcination temperature of modified coir pith showed no effect on the adsorption capacity. The sizes of modified coir pith showed a little effect on the adsorption capacity. The adsorption capacity increased with increasing of initial solution pH value up to pH of 3 and then stable. The results also corresponded with the Langmuir and Freundlich isotherms and pseudo second order kinetic adsorption models. The modified coir pith gave a higher Zn(II) and Pb(II) adsorption capacity of 29.33 mg Zn(II)/g adsorbent and 36.50 mg Pb(II)/g adsorbent, respectively.


Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4446
Author(s):  
Nouf F. Al-Harby ◽  
Ebtehal F. Albahly ◽  
Nadia A. Mohamed

Novel Cyanoguanidine-modified chitosan (CCs) adsorbent was successfully prepared via a four-step procedure; first by protection of the amino groups of chitosan, second by insertion of epoxide rings, third by opening the latter with cyanoguanidine, and fourth by restoring the amino groups through elimination of the protection. Its structure and morphology were checked using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The adsorption capacity of CCs for Congo Red (CR) dye was studied under various conditions. It decreased significantly with the increase in the solution pH value and dye concentration, while it increased with increasing temperature. The adsorption fitted to the pseudo-second order kinetic model and Elovich model. The intraparticle diffusion model showed that the adsorption involved a multi-step process. The isotherm of CR dye adsorption by CCs conforms to the Langmuir isotherm model, indicating the monolayer nature of adsorption. The maximum monolayer coverage capacity, qmax, was 666.67 mg g−1. Studying the thermodynamic showed that the adsorption was endothermic as illustrated from the positive value of enthalpy (34.49 kJ mol−1). According to the values of ΔG°, the adsorption process was spontaneous at all selected temperatures. The value of ΔS° showed an increase in randomness for the adsorption process. The value of activation energy was 2.47 kJ mol−1. The desorption percentage reached to 58% after 5 cycles. This proved that CCs is an efficient and a promising adsorbent for the removal of CR dye from its aqueous solution.


1980 ◽  
Vol 35 (8) ◽  
pp. 1009-1014 ◽  
Author(s):  
Ömer Saygin

Abstract Oxidation of substituted imidazoles with modified Fenton's reagent (Fe(II), ascorbic acid, EDTA and H2O2) in aqueous solution at pH 5-7 in the presence of inorganic ortho-phosphate gives high yields of an unknown bound phosphate, in the case of 2-methyl-imidazole up to 35% based on inorganic phosphate. The dependence of the yields on reaction parameters and the hydrolytic behaviour of the compound was studied. The products are unstable in alkaline medium and fairly stable in acid solution (half-life period ca. 1 h at 25 °C in 1 N perchloric acid). Similar bound phosphate was also observed using autoxidation with O2 instead of H2O2.


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