Adsorption of copper ions from solution using xanthate wheat straw

Area of Science:

• Materials Science
• Environmental Chemistry
• Adsorption Science

Background:

• Wheat straw (WS) is an abundant agricultural byproduct.
• Effective utilization of waste materials for environmental remediation is crucial.
• Copper ion (Cu²⁺) contamination in water poses significant environmental and health risks.

Purpose of the Study:

• To enhance the adsorption capacity of wheat straw for copper ions.
• To develop a facile grafting method for modifying wheat straw.
• To investigate the potential of modified wheat straw as an adsorbent for copper removal.

Main Methods:

• Wheat straw was modified using carbon disulfide, epichlorohydrin, and ethylenediamine to introduce xanthate groups (XWS).
• Characterization of XWS included elemental analysis, X-ray diffraction, and infrared spectroscopy.
• Adsorption experiments were conducted to determine copper ion uptake capacity, kinetics, and isotherm models.

Main Results:

• Sulfur was successfully introduced onto the wheat straw surface, forming XWS.
• Optimal Cu²⁺ adsorption occurred at pH 5, with NaCl slightly enhancing the process.
• Adsorption kinetics followed a pseudo-second-order model, and isotherms fitted the Langmuir model, yielding a capacity of 57.5 mg·g⁻¹.
• Column adsorption studies indicated the Yan model effectively predicted breakthrough curves.

Conclusions:

• Modified wheat straw (XWS) demonstrates high adsorption capacity for copper ions.
• The adsorption process is spontaneous, endothermic, and entropy-driven.
• XWS presents a viable and sustainable method for copper ion removal from aqueous solutions, utilizing agricultural waste.