High-Ionic-Strength Wastewater Treatment via Catalytic Wet Oxidation over a MnCeO_x Catalyst

Abstract

Catalytic wastewater treatment has rarely been applied to treat high-ionic-strength wastewater (HISWW) as it contains large amounts of catalyst poisons (e.g., Cl – ). This work investigates the catalytic wet oxidation (CWO) of phenol over a MnCeO x catalyst in the presence of high NaCl concentrations where the combination of MnCeO x and NaCl promoted the CWO of phenol. Specifically, in the presence of NaCl at a concentration of 200 g L –1 and MnCeO x at a concentration of 1.0 g L –1 , phenol (initially 1.0 g L –1 ) and total organic carbon (TOC) conversions were ∼98 and 85%, respectively, after a 24 h reaction. Conversely, under the same reaction conditions without NaCl, the catalytic system only achieved phenol and TOC conversions of ∼41 and 27%, respectively. In situ Attenuated Total Reflection infrared spectroscopy identified the nature of the strongly adsorbed carbon deposits with quinone/acid species found on Ce sites and phenolate species on Mn sites in the single oxides and on MnCeO x . The presence of high concentrations of NaCl reduced the carbon deposition over the catalyst, promoting surface oxidation of the hydrocarbon and reoxidation of the catalyst, resulting in enhanced mineralization. Moreover, the used MnCeO x catalyst in the salt water system was efficiently regenerated via a salt water wash under the reaction conditions, showing the great potential of MnCeO x in practical HISWW treatment.

Characterizing Bacillus globigii as a Bacillus anthracis surrogate for wastewater treatment studies and bioaerosol emissions

“…The ionic strength of influent domestic wastewater is typically between 0.003 to 0.10 M (ref. 12 and 18) while the ionic strength of digestor recycle streams can be as high as 0.17 M. 18 Many municipal wastewater treatment plants also receive significant industrial discharges, which can have ionic strength levels that exceed 1 M. [36][37][38] Since ionic strength can impact the surface properties of Bacillus spores, future studies may investigate the effects of the higher ionic strength conditions (e.g. >1 M) present when a large volumetric fraction of the influent is received from industrial sources.…”

Performance of Mesoporous Ceria-Supported Pt Catalysts for Oxidative Degradation of Aqueous Solution of Toxic Phenol in a Continuous Fixed Bed Reactor: Optimization of Reaction Conditions, Kinetics, Catalyst Stability, and Characterization

“…The maximum conversion was found to be 85% at 1.0 g/L catalyst loading and 200 g/L concentration of NaCl for the 24 h reaction duration. 29 It was observed that phenol oxidation increases with an increase in NaCl concentration since NaCl reduces the carbon deposition on the surface of the catalyst and promotes the oxidation of hydrocarbons and reoxidation of the catalyst. Besides, the salt water system facilitated the regeneration of the used catalyst via a salt water wash under reaction conditions.…”

“…The CWO of phenol was investigated by using a Mn/CeO x catalyst in the presence of NaCl. The maximum conversion was found to be 85% at 1.0 g/L catalyst loading and 200 g/L concentration of NaCl for the 24 h reaction duration . It was observed that phenol oxidation increases with an increase in NaCl concentration since NaCl reduces the carbon deposition on the surface of the catalyst and promotes the oxidation of hydrocarbons and reoxidation of the catalyst.…”