Highly Efficient Removal of Nitrate and Phosphate to Control Eutrophication by the Dielectrophoresis-Assisted Adsorption Method.

Jiaxi Li,Huiying Chen,Jianxin Xia,Qinghao Jin,Miaoying Yun,Yuran Liang,Junfeng Geng

doi:10.3390/ijerph19031890

Abstract

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.

Highlights

As is well known, nitrogen (N) and phosphorus (P) are the primary nutrients in lakes, rivers, and wetlands
Nitrogen and phosphorus support the growth of algae, bacteria, and aquatic plants in water, but too much of these elements can be harmful
Under

Summary

Introduction

Nitrogen (N) and phosphorus (P) are the primary nutrients in lakes, rivers, and wetlands. Nitrogen and phosphorus support the growth of algae, bacteria, and aquatic plants in water, but too much of these elements can be harmful. When a water body receives an excessive amount of N or P, it can be polluted by the overgrowth of algae and other aquatic plants. This eutrophication process can reduce the dissolved oxygen content, suffocate fish and other aquatic life, minimize the water transparency, reduce the overall water quality, and damage the ecological balance. Some algae can even produce toxins that are harmful to livestock and human health [1]. Nitrogen and phosphorus often exist in the form of nitrates and phosphates—the organic or inorganic compounds that contain nitrogen or phosphorus

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