Sustainable green functional nano aluminium fumarate-MOF decorated on 3D low-cost natural diatoms for the removal of Congo red dye and fabric whitening agent from wastewater: Batch & continuous adsorption process

Abstract

Industrial contaminants such as dyes being released into water streams, making the water unfit for the domestic purposes. Treatment of such dye contaminants still remains as a challenge which transformed as leading issues in environment remediation. Some of the important limitations involved in the dye adsorption includes cumbersome synthetic routes, high cost adsorbents, more contact time, lack of efficiencies and usage of more adsorbents. To address these drawbacks, present work involves facile surface modification of 3D diatoms (DE) with 2D aluminium fumarate metal-organic framework (Al-MOF) as a sustainable approach to obtain hybrid materials for the removal of industrial important toxic dyes. It is significant to note that the surface area of diatoms increased dramatically from 16.6 to 1330.8 m2g−1 revealing that the surface modifications with Al-MOF played a significant role in tuning the surface properties of DE. The developed hybrid materials were investigated for batch adsorption studies for the removal of CR dye which displayed outstanding 98.13% removal efficiency for just 20 mg of adsorbent with rapid contact time of 15 min. Moreover, the maximum adsorption capacity (qm) was found to be 181.82 mg/g, which is of better significance. Further, hybrid materials were adapted as powder-based membranes a continuous flow adsorption studies where 100 mg of materials showed excellent 99.65% of rejection performances with flux rate of 1747.1 Lm−2h−1. To demonstrate their capability in real-time sample analysis, 100 mg of hybrid materials were used for the removal of fabric whitening agent through batch adsorption and continuous flow studies exhibited with effective 94% and 99.2% efficiencies respectively. Additionally, the reusability test of adsorbents showed it could be used up to 6 cycles where the adsorbents can be regenerated with facile methanol wash. The developed hybrid materials could be one of the potential candidates for the removal of hazardous textile dye from wastewater since the adsorbent displayed rapid adsorption, efficient removal, utilization of minimal adsorbents, better reusability and finally substantiated with real time sample analysis.