Experimental Studies On Decolouring Simulating Dye Wastewater With Chitosan Wrapping Fly-ash

Printing and dyeing wastewater is a kind of industry wastewater to be hardly treated with the characteristics of high chroma and changeful colour. For the dissoluble dye in the printing and dyeing wastewater, the traditional decoloring technique can not make the wastewater clean enough to satisfy the treatment criteria at an acceptable expense. Thus, it is a difficult problem to be solved to decolour the printing and dyeing wastewater of dissoluble dye in the field of environmental protection techniques. In order to solve this problem, the lead is taken in adapting Chitosan Wrapping Fly-ash(CWF) to the flocculation and decoloring experimentation of printing and dyeing wastewater of dissoluble dye in laboratory scale studies in this thesis. The decoloring law of that the printing and dyeing wastewater of dissoluble dye is treated by CWF has been discovered. The experimental researches provide not only the basic data for the further studies of CWF disposing printing and dyeing wastewater, but also the new idea of decolouring printing and dyeing wastewater.Three kinds of simulating dye wastewater are disposed by using the homemade CWF of two different weight proportion. Taking the colour-removing rate as an index, the influences of pH value, desoge, colour of dye and blending time on the colour-removing rate and flocculation effect are investigated under the normal temperature.6 groups orthogonal experiments composed of 96 decoloring experiments and 29 single factor decoloring experiments are carried out. The analyses and reseaches of the experimental results show that: (1) The pH value is the most important factor affecting the colour-removing rate and flocculation in treating the three kinds of simulating dye wastewater by CWF. When the pH value gets aroud 4, CWF brings about a striking effect of colour-removing and flocculation. (2) CWF brings about a good effect of colour-removing to activated dye. When the pH equals 4, blending 10 min and 60mL activated-blue liquor(100mg/L), 0.05gCWF(1 : 6) could reach a colour-removing rate of 96.9%, and O.lg CWF(1: 15) could reach 93.62%. (3) CWF(1 : 6) could get the best colour-removing rates of 99.60% to feeble acidic dye and 99.53% to neutral dye. CWF(1: 15) could get the best ones of 99.23% and 98.97% to them. (4) CWF(1: 6) has better applicability and flocculation than CWF(1 : 15), and is of advantage when used to neutral dye. CWF(1: 15) is cheaper than CWF(1: 6), and is of advantage when used to feeble acidic dye.