Desalination of Brackish Waters Using Ion-Exchange Media

Abstract

An environmentally friendly method and materials study for desalinating inland brackish waters (i.e., coal bed methane produced waters) using a set of ion-exchange materials is presented. This desalination process effectively removes anions and cations in separate steps with minimal caustic waste generation. The anion-exchange material, hydrotalcite (HTC), exhibits an ion-exchange capacity (IEC) of ∼3 mequiv g-1. The cation-exchange material, an amorphous aluminosilicate permutite-like material, (Na x +2 y Al x Si1 - x O2+ y ), has an IEC of ∼2.5 mequiv g-1. These ion-exchange materials were studied and optimized because of their specific ion-exchange capacity for the ions of interest and their ability to function in the temperature and pH regions necessary for cost and energy effectiveness. Room temperature, minimum pressure column studies (once-pass through) on simulant brackish water (total dissolved solids (TDS) = 2222 ppm) resulted in water containing TDS = 25 ppm. A second once-pass through column study on actual produced water (TDS = ∼11 000) with a high carbonate concentration used an additional lime softening step and resulted in a decreased TDS of 600 ppm.

Removal of dissolved silica from industrial waters using inorganic ion exchangers

“…The SPFT test was used to measure HTC uptake of silica under more rapid flow-through conditions and to provide a measure of uptake capacity. [15] Recall that the fluid residence time in the SPFT is ~ 7 minutes; batch reaction times were carried out to 25 hours. Greater than >90% silica removal occurs rapidly and persists until ~4 hours, at which point the rate of silica removal declines (see Figure 5).…”

“…[12][13][14] In an effort to develop highly selective silica ion-exchange materials that are robust, and both cost and energy efficient, we are exploring inorganic anion exchangers like hydrotalcites (HTC) as silica adsorbents. [15] HTCs are layered double-hydroxides with…”

“…[16,17] HTC is made up of positively charged [M (II) /M (III) /OH] layers, which have a substantial anion exchange capacity of ~3 meq/g. [15,18] Our previous work showed the ability of HTC as a highly selective anion exchange material in a low energy, brackish water, desalination process. [15] This work directly relates to needs identified in the Energy-Water Nexus by the US…”

Computational and experimental study for the desalination of petrochemical industrial effluents using direct contact membrane distillation

“…Ion exchange resins have also been used frequently in industry for wastewater treatment (Battaerd et al 1973;Abdulgader et al 2013). Documented studies reported that ion exchange technologies have the capability of treating fairly concentrated brackish water (Pless et al 2006;Smith and Sengupta 2015). The advantages of ion exchange treatment is that high pumping pressures, extensive pretreatment or high thermal energy input is not required.…”

“…The advantages of ion exchange treatment is that high pumping pressures, extensive pretreatment or high thermal energy input is not required. However, the process is limited by the saturation of the resin which needs large volumes of acidic and/or basic solutions for their regeneration (Hendry 1982;Pless et al 2006;Sarkar and SenGupta, 2007).…”