Effects of adsorption interferents on removal of Reactive Red 195 dye in wastewater by chitosan

Reactive Red 195, which is an azoic anionic dye characterized by the presence of five sulfonic groups and one azoic group, is efficiently removed using chitosan. The increasing chitosan dose had a dramatic positive impact on the achieved color removal, there was approximately a linear relationship between chitosan dose and color removal of dye before color removal reach maximum. Also, the increase of dye concentration led to the increase of chitosan dosage in order to get the same color remova l.92 mg/L of chitosan dosage was sufficient to achieve complete remove of dye at initial concentration of dye at 200 mg/L. For the higher concentrations of dye, high dosages were necessary to reach complete color removal. On the other hand, the use of adsorption interferents（Fe^2＋ , Na^＋ , HCO3^- and others） can be interesting, addition of ions had effect on the color removal of Reactive Red 195. Comparing with blank, addition of chemical species approximately decreased the color removal except Na^＋ and combination of Fe^2＋ ＋ HCO3^- . However, comparing with Fe^2＋ alone and HCO3^- alone, combination of Fe^2＋ ＋ HCO3^- increased the color removal.

Dyeing and printing wastewater treatment using fly-ash coated with chitosan

Printing and dyeing industry is a considerable source of environmental contamination. In this study treatment of printing and dyeing wastewater with a new type of sewage treatment agent, fly-ash coated with chitosan particles （FCCP）, was examined. The effects ofpH, stirring time, sedimentation time and temperature on color, COD, turbidity and NH3-N removal were determined. The optimum dosage of FCCP and the influence of individual factors on removal efficiency were tested. The optimum parameters determined using the L16 （45） orthogonal experiment were as follows： FCCP （weight ratio of chitosan to fly-ash 1：6） dosage, 4 g.L^-1; temperature, 35℃; pH, 4. The stirring time and sedimentation time were 20 min and 5 h, respectively. Under these optimum conditions, the color, COD and NH3-N removal ratios were 97%, 80% and 75%, respectively.

Combination of adsorption and biodegradation processes for textile effluent treatment using a granular activated carbon-biofilm configured packed column system

The objective of this study was to investigate the feasibility of using a granular activated carbon-biofilm configured packed column system in the deeolodzation of azo dye Acid Orange 7-containing wastewater.The Acid Orange 7-degrading microbial from anaerobic sequencing batch reactor which treating the azo dye-containing wastewater for more than 200 d was immobilized on spent granular activated carbon(GAC)through attachment.The GAC-biofilm configured packed column system showed the ability to decolorize 10...

Nighttime image dehazing using color cast removal and dual path multi-scale fusion strategy

Nighttime image dehazing aims to remove the effect of haze on the images captured in nighttime,which however,raises new challenges such as severe color distortion,more complex lighting conditions,and lower contrast.Instead of estimating the transmission map and atmospheric light that are difficult to be accurately acquired in nighttime,we propose a nighttime image dehazing method composed of a color cast removal and a dual path multi-scale fusion algorithm.We first propose a human visual system(HVS)inspired color correction model,which is effective for removing the color deviation on nighttime hazy images.Then,we propose to use dual path strategy that includes an underexposure and a contrast enhancement path for multi-scale fusion,where the weight maps are achieved by selecting appropriate exposed areas under Gaussian pyramids.Extensive experiments demonstrate that the visual effect of the hazy nighttime images in real-world datasets can be significantly improved by our method regarding contrast,color fidelity,and visibility.In addition,our method outperforms the state-of-the-art methods qualitatively and quantitatively.