title: Novel pre-treatment of zeolite materials for the removal of sodium ions: potential materials for coal seam gas co-produced wastewater.
abstract: Coal seam gas (CSG) is the extraction of methane gas that is desorbed from the coal seam and brought to the surface using a dewatering and depressurisation process within the saturated coalbed. The extracted water is often referred to as co-produced CSG water. In this study, co-produced water from the coal seam of the Bowen Basin (QLD, Australia) was characterised by high concentration levels of Na(+) (1156 mg/L), low concentrations of Ca(2+) (28.3 mg/L) and Mg(2+) (5.6 mg/L), high levels of salinity, which are expected to cause various environmental problems if released to land or waters. The potential treatment of co-produced water using locally sourced natural ion exchange (zeolite) material was assessed. The zeolite material was characterized for elemental composition and crystal structure. Natural, untreated zeolite demonstrated a capacity to adsorb Na(+) ions of 16.16 mEq/100 g, while a treated zeolite using NH4 (+) using a 1.0 M ammonium acetate (NH4C2H3O2) solution demonstrated an improved 136 % Na(+) capacity value of 38.28 mEq/100 g after 720 min of adsorption time. The theoretical exchange capacity of the natural zeolite was found to be 154 mEq/100 g. Reaction kinetics and diffusion models were used to determine the kinetic and diffusion parameters. Treated zeolite using a NH4 (+) pre-treatment represents an effective treatment to reduce Na(+) concentration in coal seam gas co-produced waters, supported by the measured and modelled kinetic rates and capacity.
authors.affiliation: School of Medical and Applied Sciences, CQUniversity, Rockhampton, QLD 4701 Australia.
authors.forename: Oscar
authors.initials: O
authors.lastname: Santiago
authors.affiliation: School of Medical and Applied Sciences, CQUniversity, Rockhampton, QLD 4701 Australia.
authors.forename: Kerry
authors.initials: K
authors.lastname: Walsh
authors.affiliation: School of Medical and Applied Sciences, CQUniversity, Rockhampton, QLD 4701 Australia ; Arris Pty Ltd, Rockhampton, QLD Australia.
authors.forename: Ben
authors.initials: B
authors.lastname: Kele
authors.affiliation: School of Medical and Applied Sciences, CQUniversity, Rockhampton, QLD 4701 Australia.
authors.forename: Edward
authors.initials: E
authors.lastname: Gardner
authors.affiliation: School of Medical and Applied Sciences, CQUniversity, Rockhampton, QLD 4701 Australia.
authors.forename: James
authors.initials: J
authors.lastname: Chapman
keywords: CSG water management; Coal seam gas (CSG); Ion exchange; Saline water; Water treatment; Zeolite