Removal of organic matter and ammonia nitrogen from contaminated water by combining hydrotalcites pretreatment and ultrafiltration

In this study, the combined process of hydrotalcite and ultrafiltration was investigated for the treatment of micro-polluted water samples. The study examined the impact of the combined process on the elimination of Total Organic Carbon (TOC) and ammonia nitrogen, varying the dosage of hydrotalcite, the duration of adsorption, and the volume of ultrafiltration backwash water. The experimental outcomes were subjected to analysis. Utilizing response surface methodology, the conditions for the removal of ammonia nitrogen were optimized through single-factor experiments. The results indicated that the interaction of the three factors had a significant impact on the removal of ammonia nitrogen, with the order of significance being: hydrotalcite dosage & adsorption time > adsorption time & backwash water volume > hydrotalcite dosage & backwash water volume. Upon administering an hydrotalcite dosage of 298.25 mg/L, maintaining an adsorption time of 50.49 minutes, and utilizing a backwash water volume of 153.42 L/h, the maximum removal rate of ammonia nitrogen achieved was 73.52%. Through the regeneration performance experiment, it is found that hydrotalcite has a good retention rate and can be reused. And under the prevailing conditions, the combined treatment process achieved the following pollutant removal rates: turbidity reduction of 97.60%, ammonia nitrogen removal of 71.25%, Cr (VI) elimination of 93.41%, and Mn (II) removal amounting to 33.33%. This study offers theoretical support for the future application of ultrafiltration membranes.