Novel Graphene‐Based Foam Composite As a Highly Reactive Filter Medium for the Efficient Removal of Gemfibrozil from (Waste)Water

This is the final version. Available on open access from Wiley via the DOI in this recordData Availability Statement; The data that support the findings of this study are available in the supplementary material of this article.Graphene-based materials have emerged as alternative adsorbents, but their success in removing pharmaceutical contaminants has been limited due to degradation caused by restacking and limited control over their sizes and porosities. Driven by this issue, in the current study, to counteract the restacking behavior, graphene sheets are supported on a thread/rod-like matrix structure in a boron nitride foam material, and a novel porous composite foam-supported graphene is synthesized. The as-prepared novel composite offers extraordinary features, such as high absorption kinetics, large available surface area, high porosity (>98%), ecofriendliness and cost-effective synthesis, and excellent affinity to emerging pharmaceutical contaminants. When batch-testing graphene-based foam material and porous graphene nanosheets to remove gemfibrozil (GEM) from wastewater samples, rapid adsorption kinetics (<5 min) are exhibited by the graphene-based foam. Column filter studies are conducted for both materials to test their performance in removing GEM from distilled water, synthetic graywater, and actual wastewater. Overall, the foam composite-based filter marginally outperforms the sand-supported graphene filter and significantly outperforms the unsupported graphene filter. A numerical MATLAB model is developed to simulate the reactive solute transport of GEM influent through the foam filter. Also, a formal sensitivity analysis is conducted to identify the key parameters influencing the model results.Department of Science and Technology, Government of IndiaNatural Environment Research Council (NERC

Multi-functional magnesium hydroxide coating for iron nanoparticles towards prolonged reactivity in Cr(VI) removal from aqueous solutions

In this study, the reactive performance of magnesium hydroxide-coated iron nanoparticles (Fe @Mg(OH)2) was investigated for the removal of hexavalent chromium (Cr(VI)) from aqueous solutions. Short-and long-term progressive-release of Fe @Mg(OH)2 reactivity was evaluated through several batch tests. The Multi-functional effect of the environmentally-friendly Mg(OH)2 coating shell was represented by the progressive shell-dissolution in water and preventing the rapid corrosion of Fe-core, which resulted in a controlled release of Fe reactivity towards Cr(VI). Fe @Mg(OH)2 showed good performance in preserving Fe long-term reactivity within a wide range of pH (3.0-9.0) and temperature (15-55 oC). The long-term investigation of Fe @Mg(OH)2 performance towards Cr(VI) removal confirmed the progressive and maintained reactivity, represented by the continuous release of Fe electrons, to achieve 100% removal efficiency of 40 mg/L initial Cr(VI) concentration over 50 days reaction time, to be reported for the first time in the literature. Fe @Mg(OH)2 showed high regeneration abilities up to 5 cycles with 1.36 times average enhancement in Cr(VI) removal efficiency compared to that of Fe. Moreover, Fe @Mg(OH)2 achieved an increase in the shelf-live longevity performance up to 30 days without any storing solution with 90% final Cr(VI) removal efficiency after 180 min reaction time

Investigating the design parameters for a permeable reactive barrier consisting of nanoscale zero-valent iron and bimetallic iron/copper for phosphate removal

There is a growing interest in deploying nanoscale zero valent iron (NZVI) in permeable reactive barriers (PRBs) for groundwater remediation. In the present study a series of packed-column experiments were conducted in order to investigate the effectiveness of phosphorus removal from groundwater using NZVI and bimetallic NZVI/Cu as reactive materials within PRBs. Seven sets of packed-column experiments were conducted in order to study the effect of different design parameters for PRB; including delivery approach of NZVI into porous media, PRB's configuration, coexisting groundwater ions and change in flowrate. Results implied that doping NZVI surface with copper had an anti-aggregation effect and enhanced its performance in terms of phosphorus removal 2.2 times higher than bare NZVI. Moreover, the lower flowrate (10 ml/min) demonstrated improved phosphorus removal by 22% compared with higher flowrate (60 ml/min). Additionally, groundwater ions barely interfered phosphorus removal process with only ±6%. Overall, geochemical properties and characteristics of the supporting materials were key parameters in the removal process of phosphorus by NZVI/Cu