Removal of Saline Water Hardness by Different Sorbents

Total hardness (TH) of water causes numerous problems in life and industry, that shows the necessity of water hardness removal. In this research, different sorbents such as almond shell, wheat husk, rice husk, sawdust, zeolite, bentonite and activated carbon in raw state, acid-activated and alkaline-activated conditions for removing Ca, Mg and therefore, water hardness were used. The results of this study showed that some of sorbents needed to be activated by acid or base to remove calcium, magnesium and hardness of the brine solution in different salinities. In salinity of 20 dS m-1,acidic-activation of rice husk, sawdust, zeolites and activated carbon increased Mg removal from saline water. In this salinity, alkaline-activation of almond shell and bentonite and likewise acidic activation of wheat and rice husk enhanced Ca removal from saline water. Moreover, alkaline activation of almond shell and bentonite and likewise acidic activation of sawdust, wheat and rice husk caused reduction of saline water hardness. Removal percentages of calcium, magnesium and hardness for salinity of 9 dS m-1 were greater than those for the salinity of 20 dS m-1.