Author(s)

Mihaela Ciopec, Iosif Hulka, Narcis Duteanu, Adina Negrea, Oana Grad2, Petru Negrea, Vasile Minzatu & Cristina Ardean

Abstract

One of the strategies for sustainable development is to promote a quality health care system, available to all without discrimination, and improving protection against health threats. In this context, arsenic removal from groundwater for drinking purposes presents challenges at national and global levels. Thus, the present article focuses on removing arsenic from groundwaters by using a new class of materials based on cellulose modified with crown ether (dibenzo-18-crown-6) doped with iron ions. Using such extractants involves only a small amount of crown ether, indicating higher efficiency of produced material, and in order to improve the adsorbent properties and selectivity for arsenic removal, the modified cellulose was functionalized with iron ions.

The new adsorbent material was characterized by using energy-dispersive X-ray analysis and Fourier-transform infrared spectroscopy. To investigate its adsorption properties for arsenic removal, equilibrium, kinetic and thermodynamic studies were performed. Arsenic adsorption from water onto new class of adsorbent material was studied under different experimental conditions such as reac- tion time, initial arsenic concentration and temperature. Kinetic of adsorption process was better de- scribed by pseudo-second-order model. The equilibrium adsorption data were well described by the Sips adsorption isotherm. The values of thermodynamic parameters (ΔGº, ΔHº, ΔSº) showed that the adsorption process was endothermic and spontaneous.

The possibility of reuse of the adsorbent material through adsorption and desorption cycles was also studied, and it was found that the material can be used in three adsorption–desorption cycles. 

Keywords

crown ethers, arsenic, adsorption, iron ions, water.