Investigation of nitrate removal from aqueous solution by Clinoptilolitezeolite modified with Cu and Zn

Nitrate entered into the human body is transformed into nitrite through processes that combinewith amines and cause the formation of nitrosamine, which is a carcinogenic substance. Accordingto research, nitrate also causes Alzheimer's disease[۱]. Therefore, it is necessary to remove nitratefrom water. In this research work, due to the low efficiency of unmodified clinoptilolite zeolite,zinc chloride and copper acetate were used to modify the adsorbent. Various factors such asenvironmental pH, nitrate concentration, contact time and adsorbent dosage were investigated. Theresults showed that the modified zeolite is more efficient in removing nitrate from aqueoussolutions due to the different adsorption sites, the simplicity of the system and the high removalefficiency compared to the unmodified zeolite. The results of the effect of contact time on theamount of nitrate removal after modification of the adsorbent by both substances show that themaximum was reached with the increase of the contact time from ۲ to about ۸۰ minutes and thenwith the excessive increase of the contact time, the efficiency decreased gradually. The increasein efficiency at early contact times may be due to the increase in the number of vacant sites on theadsorbent surface. After the period of time when the empty sites were occupied, the amount ofremoval of the adsorbent depends on the activity of the added substance, in this case, copper acetatehas removed the nitrate particles more strongly.Therefore, in high concentrations of nitrate, zeolitemodified with zinc chloride was the most suitable adsorbent, while in low concentrations of nitrate,zeolite modified with copper acetate showed the highest removal efficiency.

Keywords:

Zeolite , clinoptilolite , nitrate removal , zinc chloride , copper acetate