Sulfonation of Carbonaceous Products by Wet Dehydrochlorination of Poly(vinyl chloride) (Part 1) -Utilization as a Collector of Heavy Metals-

Abstract

For the purpose of utilization of waste plastics, the product obtained from wet dehydrochlorination of poly (vinyl chloride) (PVC) was converted into an ion exchanger by treating it with sulfuric acid. This may be applicable as a collector of heavy metals. The wet dehydrochlorination products were prepared in the presence of NaOH (Product 1) or Fe (Product 2) under nitrogen atmosphere by the use of pelleted PVC or in the presence of NaOH and FeA (ProduCt 3) un-cter oxygen atmosphere by the use of powdered PVC. By sulfuric acid treatment sulfonic and carboxyl groups were introduced into the carbonaceous products. The amount of the sulfonic group introduced was nearly independent of treating temperature, reaching about 2: theq/g, Whereas the amount of the carboxyl group introduced increased with rising temperature. The ion 'exchangers containing 2 nieq/g of sulfonic, group and 2 meq/g of carboxyl group were converted into Na- or H-from, . and a solution containing 0.00612 moll/ of each Cua+, Zn²⁺, c42+ or Hg²⁺ was allowed to flow through them at SV=4, -5 to prepare break through curves. The presence of slow exchange part was noted in H-form and this part was inferred to be due to the carboxyl group.
The ion exchanger obtained from Product 1 showed the following order in the amounts of exchange: Cu²⁺>Cd²⁺, Ni²⁺, Zn²⁺>Hg1+ form Na-for and Cu"- >Zn²⁺, Cd²⁺>Ni2>Hg²⁺ for H-form. The same is true for the ion exchanger obtained from Product 2: Cd²⁺, Ni²⁺, Zn²⁺, Cu²⁺>Hg²⁺ for Na-form and Cu²⁺ >Cd²⁺, Ni²⁺, Zn²⁺>Hg²⁺ for H-form, and for the spherical ion exchanger form Product 3: Cu²⁺, Cd²⁺, Ni²⁺, Zn²⁺>Hg²⁺ for Na-form and Cul+, Cd²⁺, Ni²⁺, Zn1+>Hg²⁺. for, H-form.
Virtually ion exchange of Hg²⁺ does not occur on ion exchanger of H-form but beside ion exchange, such interaction as adsorption due to activated carbon is observed on ion exchanger of Na-form and the precipitation of mercury(I) chloride results on the surface of exchanger.