Cyclic organic carbonate modification of sodium bentonite for enhanced containment of hyper saline leachates

Two cyclic organic carbonates (COC), propylene carbonate (PC) and glycerol carbonate (GC), were investigated as saline-resistant modifying agents of Na+-montmorillonite using X-ray diffraction (XRD) and Fourier transform infrared (FTIR). PC has been studied previously and has been used as an effective amendment material of Na+-bentonite for saline applications. In this research GC is proposed as a more effective modifying agent for containing hyper saline leachates. Na+-montmorillonite was reacted with up to 1 N sodium chloride (NaCl) and calcium chloride (CaCl2) salt solutions to assess changes in the interlayer spacing (i.e., d-value of the 001 reflection in XRD traces) due to osmotic desiccation, as well as to investigate the mechanism and strength of bonding between GC/PC and Na+-montmorillonite by FTIR. GC/Na+-montmorillonite was strongly resistant against strongly saline sodic salt solution compared to PC/Na+-montmorillonite. CaCl2 solution had a more detrimental effect on COC modified Na+-montmorillonite, however, GC/Na+-montmorillonite appeared to retain more intercalated COC than PC/Na+-montmorillonite when leached by strong calcic salt solutions.