Water softening by combination of ultrasound and ion exchange

Abstract

Ion exchange resin used in this work was styrene-divinylbenzene co-polymer with sulfonic acid group as a strong acid cation resin. This resin is particularly well suited for the removal of water hardness. In water treatment, commonly used softening processes are chemical precipitation and ion exchange. In this study, a combination of ultrasound and ion exchange was applied for reducing the hardness of water. The rate of exchange or kinetics of ion exchange is governed by several parameters. Therefore, important variables such as intensity of ultrasound, amount of resin, concentration of ions and contact time were investigated. The experimental data related to the removal of magnesium and calcium ions were fitted properly with Langmuir model. The kinetic of removal for both ions was pseudo-first-order. In point of mechanism, the internal porous and film diffusion were both effective in the process. The capacity of sorption and the velocity of removal were higher in the presence of ultrasound than control method and this is related to the cavitation process.

Effect of ultrasound on the kinetics of cation exchange in NaX zeolite

“…Furthermore, ultrasonic method is more effective than the traditional one. This can be explained with the theory of ''hot spots'' [5]: Hot spots increase the temperature and pressure near the surface of the NaX zeolite causing enhancement in the cation exchange as observed during removal of water hardness [15]. The effect of ultrasonic method on Ce 3+ exchange was also seen when compared with the traditional one.…”

Bench-Scale and Pilot-Scale Treatment Technologies for the Removal of Total Dissolved Solids from Coal Mine Water: A Review

“…, Mg 2? and other bivalent and trivalent metals (Entezari and Tahmasbi 2009;Escobar et al 2006;Yildiz et al 2003). In general, these are complex systems that need optimization of several parameters (e.g.…”

Electrochemical water softening in a diaphragm electrolyzer

“…Regeneration solutions are discharged into water reservoirs thereby increasing their mineral composition, which negatively affects the environment. To improve efficiency of the ion-exchange process, combinations of different methods are used [5].…”