The removal of excessive amounts of nitrate and phosphate from water sources, especially agricultural wastewater, has been of high significance to control eutrophication in aquatic systems. Here, a new method is reported for the removal of nitrate and phosphate simultaneously from wastewater based on the combination of the solution-phased adsorption (ADS) and dielectrophoresis (DEP) techniques. The plant ash was first selected as the adsorbent by screening tests, followed by a systematic investigation of using the adsorbent to remove nitrate and phosphate from wastewater under various experimental conditions, including the testing of adsorbent dosage, pretreatment time, water flow rate, and electrode voltage. The analysis of the adsorbent particles was also performed by scanning electron microscope (SEM) analysis, the energy dispersive X-ray spectroscopy (EDX) test, and the measurement of Zeta potentials. Compared with the ADS method alone, the introduction of DEP into the purification process has greatly increased the removal rate by 66.06% for nitrate and 43.04% for phosphate, respectively. In the meantime, it is observed that the processing time has been greatly reduced by 92% with the assistance of DEP.

A new approach, based on dielectrophoresis (DEP), was developed in this work to enhance traditional adsorption for the removal of ammonia nitrogen (NH₃-N) from wastewater. The factors that affected the removal efficiency were systematically investigated, which allowed us to determine optimal operation parameters. With this new method we found that the removal efficiency was significantly improved from 66.7% by adsorption only to 95% by adsorption-DEP using titanium metal mesh as electrodes of the DEP and zeolite as the absorbent material. In addition, the dosage of the absorbent/zeolite and the processing time needed for the removal were greatly reduced after the introduction of DEP into the process. In addition, a very low discharge concentration (C, 1.5 mg/L) of NH₃-N was achieved by the new method, which well met the discharge criterion of C < 8 mg/L (the emission standard of pollutants for rare earth industry in China).

A controlled synthesis of titanium dioxide nanoparticles (TiO₂-NPs) with uniform size and a specific crystal structure could be achieved by a combined sol gel/dielectrophoresis (DEP) approach. The applied voltage could influence the crystal structure and particle size.

A newly designed apparatus and process, including dielectrophoresis and adsorption to efficiently remove cadmium species from wastewater, is reported in this study. With this technique, cadmium ions are firstly adsorbed by shell powder particles, which are subsequently trapped and concentrated by a dielectrophoresis process. The factors affecting the metal removal efficiency are systematically investigated, which allows us to determine the optimal operation conditions. Our experimental data indicate that via the adsorption and dielectrophoresis steps, cadmium can be almost completely removed from wastewater as evidenced by the very high removal efficiency of 99.4%. This suggests that our dielectrophoresis-assisted adsorption approach is highly effective for the removal of cadmium, and the technique could be extended to the removal of other heavy metal ions from wastewater as well.