Removal of ions from produced water using Powder River Basin coal

In addition to being used as an energy source,coal also has significant potential for other,more sustainable uses including water treatment.In this study,we present a simple approach to treat water that was produced during oil production and contained a total dissolved solids(TDS)content of over 150 g/L using Powder River Basin(PRB)coal.PRB coal used as packing material in a flow-through column effectively removed 60%–80%of the cations and anions simultaneously.Additionally,71%–92%of the total organic carbon in the produced water was removed as was all of the total suspended solids.The removal mechanisms of both cations and anions were investigated.Cations were removed by ion exchange with protons from oxygen-containing functional groups such as carboxylic and phenolic hydroxyl groups.Anions,mainly Cl−1,appeared to be removed through either the formation of resonance structures as a result of delocalization of electrons within coal molecules or through ion–πinteractions.We propose that coal is a“pseudo-amphoteric”exchange material that can remove cations and anions simultaneously by exchanging ions with both ionized and non-ionized acids that are ubiquitous in coal structure or resonance effect.

Influence of drying and calcination temperatures for Ce-Cu-Al trimetallic composite catalyst on simultaneous removal H_(2)S and PH_(3):Experimental and DFT studies

This work explored the influences of the drying and calcination temperatures on a Ce-Cu-Al trimetallic composite catalyst for the simultaneous removal of H_(2)S and PH_(3).The effects of both temperatures on the structural features and activity were examined.The density functional theory method was used to calculate adsorption energies and further analyze their adsorption behavior on different slabs.Experiments revealed suitable drying and calcination temperatures to be 60 and 500℃,respectively.The capacity reached 323.8 and 288.1 mg/g.Adjusting drying temperature to 60℃is more inclined to form larger and structured grains of CuO.Rising calcinating temperature to 500℃could increase the grain size and redox capacity of CuO to promote performance.Higher temperatures would destroy the surface structure and lead to a crystal phase transformation,which was that the CuO and Al_(2)O_(3)were gradually recombined into CuAl_(2)O_(4)with a spinel structure.The exposed crystal planes of surficial CuO and CuAl_(2)O_(4)were determined according to characterization results.Calculation results showed that,compared with CuO(111),H_(2)S and PH_(3)have weaker adsorption strength on CuAl_(2)O_(4)(100)which is not conducive to their adsorption and removal.