Method for processing wastewater with high content polyvinyl alcohol

Abstract

The invention which mainly aims to solve technical problems existing in the prior art provides a method for processing wastewater with high content polyvinyl alcohol. The method comprises the following steps: 1, 0.5-3.0 wt% of sodium sulfate and 0.5-3.0 wt% of sodium chloride which are used as salting-out agents are added to the wastewater to reduce the solubility of polyvinyl alcohol in the wastewater and dissolve partial polyvinyl alcohol out, and the partial polyvinyl alcohol is suspended; 2, one hour later, the partial polyvinyl alcohol is fibrous in shape, 0.05-0.30 wt% of borax is added, sodium hydroxide is added to adjust the pH value of the wastewater to 8-9, a didiol structure is generated through crosslinking borax with polyvinyl alcohol under weak alkaline environment to slowlyflocculate single polyvinyl alcohol fibers; and 3, three hours later, 0.05-0.30 wt% of aluminum chloride is added when the polyvinyl alcohol fibers are flocculated into a cluster to make the flocculated polyvinyl alcohol fibers acceleratedly settle, wherein aluminum chloride is used as a precipitating agent.

Description

technical field [0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a method for treating wastewater with high content of polyvinyl alcohol. Background technique [0002] In the prior art, in the recycling process of special paper added with polyvinyl alcohol as a strengthening agent, the method of hot water cooking is used to recycle the plant fibers in the scraps of special paper, and the waste water after cooking contains a large amount of polyvinyl alcohol (6-10g / l), the COD value is as high as 6000-15000, direct discharge will cause serious pollution; directly into the papermaking water circulation system, it is easy to cause the water quality of papermaking water to deteriorate, and the bonding effect of polyvinyl alcohol also affects production stability and product quality. Polyvinyl alcohol has a 1,3-ethylene glycol structure and is a non-ionic organic polymer. The adsorption effect of the charge on it is very w...

AI Technical Summary

Problems solved by technology

At the same time, although the polyvinyl alcohol content in the aforementioned waste water is huge, it still cannot be easily extracted from the waste water. Designed to recover polyvinyl alcohol, the main method is to further increase the concentration of polyvinyl alcohol by ultrafiltration, and then process to extract polyvinyl alcohol

However, this method cannot be applied to industrial wastewater treatment and recovery, because polyvinyl alcohol is a viscous substance, which can easily block the ultrafiltration membrane, resulting in a very long ultrafiltration process, and the use cost of the ultrafiltration membrane is greatly increased.