Goethite/montmorillonite adsorption coupled with electrocoagulation for improving fluoride removal from aqueous solutions.
Jiali KangJunfeng LiChengxiao MaLijuan YiTiantian GuJiankang WangShenglin LiuPublished in: RSC advances (2022)
With the increasing problem of fluoride pollution, it is urgent to find an efficient method to remove fluoride (F - ). In this study, a new material goethite-montmorillonite-sorbent (GMS) was prepared and added into the electrocoagulation (EC) reaction to form a new pathway (EC/GMS) for the removal of fluoride. Scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), Fourier-transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS) and other characterization methods were used to analyze the properties of GMS. The fluoride removal performance and mechanism of EC/GMS was studied. The results showed that GMS could provide numerous adsorption sites. EC/GMS could achieve a high removal efficiency of 95.98% and lower energy consumption of 0.58 kW h m -3 for 60 min. EC/GMS could achieve a removal efficiency of 99.47% after optimization by single-factor experiments and RSM-BBD optimal experiments. Meantime, the removal rate of the EC/GMS still reached over 87% after six cycles. The kinetic analysis indicated that the degradation pathways could also achieve a high removal rate for high fluoride-containing concentration solutions within a short time. The stretching vibration of C-F and C-O and the existence of F - revealed that the electrophoresis of the electrodes, adsorption of GMS, and co-precipitation of flocs were the main removal pathways, and the accelerating effect between the electrocoagulation and adsorption process was addressed. This study provides a new pathway for removing fluoride from aqueous environments.