ADSORPTION OF MODEL WHITEWATER CONTAMINANTS ON ION-EXCHANGE RESINS

摘要

Significant efforts towards closed-cycle papermaking operations will be required to reduce fresh water consumption and reject loads. Unfortunately, severe drawbacks on paper machine runnability and paper quality are occurring as water consumption is reduced due to a build-up of dissolved and colloidal substances (DCS) in process waters. Adsorption of DCS on high surface area solid sorbents is proposed to remove them from process waters prior to recycling. Adsorption potential of polygalacturonic (PGA) and abietic acids (AA) on ion-exchange resins was studied. These resins had different functional groups and/or porosities. Optimum adsorption was achieved with a gel-type (microporous) resin containing tertiary amine groups. Under experimental conditions studied, adsorption reached 19 mg PGA/g and 45 mg AA/g after 15 minutes. Isotherms revealed that at pH 5.5, PGA was adsorbed in multiple layers, while AA formed a monolayer. Kinetic studies suggested that dissolved substances (PGA) could diffuse in the pores, whereas this was not the case for colloidal substances (AA).