On-line Tracked Studies On Solid-liquid Adsorption Behavior By Potentiometry

Computer automatic data acquisition system integrated with potentiometeric method was used to on-line tracing studies the solid-liquid adsorption system behavior. This method has been proved easy to be grasped, and avoided the traditional intermittent analytic method arduous work load. A computational program was devised to calculate, fit and plot the experimental data, which not only avoided human computational errors, but also gave a possibility to check, adjust and optimize the experimental condition parameters. A good foundation will be found for the following work on solid-liquid adsorption behaviors by computer-aided multi-channel synchronization data acquisition with potentiometer.In this paper, traditional intermittent analytic method and potentiometeric method were compared by studying the adsorption of low concentration potassium hydrogen phthalate on D354, which is one of weak base ion exchange resins. The influence of concentration of ethanol on rate of adsorption was discussed in ternary system, exploring the influence of different substitution groups and substitution position as well as salt on adsorption.The apparent adsorption rate constant(K), the interaction energy between solid and liquid(U), and the adsorption potential between solid and liquid(E) were all determined by the solid-liquid interface adsorption kinetic equation, which was facile, time-saving, in-situ, and more sensitive compared with the traditional method.The information was revealed from the results as below:1. Through potentiometeric method with the traditional intermittence type analytic method contrast, the experimental result indicated the computer-aided potentiometeric method conforms to the solid-fluid adsorption system experimental requirement. This method is easy to carry out, which provides a new approach to investigate binary and ternary solid-liquid adsorption experiments.2. The adsorption process of low concentration electrolyte on resins obeys monolayer adsorption mechanism.3. For the same adsorption temperature, the adsorption rate of potassium hydrogen phthalate on D354 decreased with increasing the initial adsorbate concentration.4. The adsorption rate of benzoic acid on CCTS decreased with the increasing of ethanol in solution system.5. When CCTS adsorbs the derivative of benzoic acid, the substituted position affects the adsorption rate, result as follows: k_{p-nitrobenzoic acid} > k_{benzoic acid} > k_{p-Chlorobenzoic} acid > k_{p-Hydroxyl benzoic acid}.6. When CCTS adsorbs the chlorobenzoic acid, the adsorption rate has the following rule: k_{p-chlorobenzoic acid} > k_{m-chlorobenzoic acid} > k_{o-chlorobenzoic acid}.7. Addition of salt accelerated the adsorption of benzoic acid on CCTS. The adsorption rate increased with an increase of the salt concentration. A good explanation can be given by the salt effect theory.