Copper foams in water treatment technology: Removal of hexavalent chromium

Abstract

Open-cell copper foams were prepared using a space holder technique and tested as filter-beds for the uptake and reduction of Cr(VI) in drinking water. The use of raw cane sugar as a space holder provides an environmentally friendly method for the production of foams with controllable porous network characteristics. Specifically, by applying a sugar volume of 70-80 % with particle sizes in the range of 0.35-0.70 mm, it was possible to obtain final porosity of 65 %, high structural stability, and enhanced interconnectivity of macropores required for the free flow of treated water. Smaller sugar particles ensure a smaller pore size and a higher specific surface area, favoring the interaction of water with the effective copper surface. Column tests indicated that a realistic filtering system using the Cu-foam can operate with complete Cr(VI) removal and minimum Cu leaching in the pH 7±0.2 range, capturing chromium in the form of Cr(III) and Cr(VI) oxides. Chromium is homogeneously distributed and incorporated into the copper porous network allowing an almost unlimited lifetime of effective use compared to common adsorbents.

Technologies for Decentralized Fluoride Removal: Testing Metallic Iron-based Filters

“…Because steel wool is simply the starting material for a hand-built and locally sourced water filter, there is a real potential to foster local industry during filter construction, which includes: (i) designing and manufacturing plastic or glass filter containers; (ii) purchasing and conditioning Fe 0 materials (including steel wool) and additives; and (iii) collecting and recycling spent (corroded) filters [122,127,169,176]. Testing metal foams should be also considered in this effort [177]. In summary, the demand for decentralized water treatment can be exploited to start a new area of self-reliance in the developing world.…”

Effect of Porous Metal Flow Field in Polymer Electrolyte Membrane Fuel Cell under Pressurized Condition

“…Metal foam materials have been applied to several fields, e.g., medicine, filter industries, and energy engineering, caused by their metallic properties and high porosities . Recently, metal foam materials have also been utilized for energy devices, e.g., secondary batteries, water electrolyzers, and solar cells .…”

Hierarchical nanoparticle-induced superhydrophilic and under-water superoleophobic Cu foam with ultrahigh water permeability for effective oil/water separation

“…Besides, Cu foam also shows enormous potential in the field of heat transfer 24 and removal of heavy metal ions. 25,26 Oil/water separation faces severe challenges due to the frequent crude oil spill accidents and the increasing amount of industrial wastewater. In contrast to traditional membrane separation, gravity-driven oil/water separation is more efficient, either flux or energy-cost, among which superhydrophilic membranes possess superior advantages like anti-pollution, easier recycle etc..…”