110th Anniversary : Industrial ProcessWater Treatment and ReuseEnabled by Selective Ion Exchange Materials

Silica (SiO2) is ubiquitous in petroleum produced waters; removal and recovery of silica reduces fouling when upcycling these waters for industrial applications. Herein, we report the relevant properties of a selective silica recovery material, calcined hydrotalcite (HTC), as well as the design and economic analysis for its use in an ion exchange process to remove silica from produced water. This process improves upon established technologies by minimizing sludge product, reducing process fouling, and lowering energy use. The ion exchange capacity of HTC (approximately 45 mg SiO2/g HTC) and optimized thermal reaction conditions (550 °C for 30 min) for calcination and regeneration were determined experimentally and used in the process modeling. Modeling outputs included raw material requirements, energy use, and the minimum water treatment price (MWTP). Monte Carlo simulations for process economics showed how R&D improving HTC reusability and silica binding capacity as well as separate reductions in raw ma...