Fabrication of bentonite nanosheets from natural bentonite using ultrasonic-assisted liquid phase exfoliation method and its application for adsorptive removal of Methylene Blue from water

Abstract

Clays (especially bentonite) are widely used as barriers in landfills to prevent contamination of subsoil and groundwater by leachate containing heavy metals or toxic organics. However, the future application of bentonite nanomaterials is still limited due to complicated and expensive preparation process requiring several steps, toxic chemical agents, or additional surfactants. In this study, a green approach was proposed to produce bentonite nanoplatelets by an ultrasound-assisted liquid-phase exfoliation method using natural clay minerals containing bentonite as a precursor. The materials were then characterized by SEM, BET, AFM and XRD. The produced material was used to remove methylene blue (MB) from aqueous solution by batch adsorption. Results showed that the bentonite nanoplatelets gave high adsorption ability with Langmuir maximum adsorption capacity of 312.50 mg/g, which could be a good adsorbent for removing dyes and other toxic organics in wastewater.

Factors controlling groundwater Arsenic concentration in the Red River Delta, Vietnam

“…The content of TDS in the groundwater is related to the process of geological evolution in the past, for marine sediments As is related to the reduced SO4 concentration in the groundwater mentioned in section 2.4, so the water with high TDS is the lower the As content and vice versa. On the basis of the map of groundwater salinity zones in the RRD [25,45] and the monitoring data of the National Monitoring Network in 2018 [45], the groundwater TDS in the aquifers is divided into 3 scores in Table 4 and classified as shown in Figure 7. 5.…”