Ecofriendly Synthesis of Copper Nanoparticles Using Coriander Seeds for Enhanced Adsorption Efficiency

Domestic gas cylinders are widely used in Iraq, and due to frequent usage and improper maintenance, organic sulfur group deposits accumulate. These deposits emit a pungent, harmful odor, and improper disposal methods, such as discarding cylinders in soil or rivers, pose environmental risks. Therefore, a need exists for an efficient and environmentally friendly method to remove these deposits.

This study aims to develop a green and safe method for removing organic sulfur group deposits from domestic gas cylinders using copper nanoparticles (CuNPs) synthesized through green chemistry.

Copper nanoparticles were synthesized using hot and cold aqueous extracts of coriander seeds (Coriandrum sativum L.) as reducing and stabilizing agents, with a 1mM aqueous solution of CuSO₄•5H₂O. The formation of CuNPs was confirmed by color change and UV-visible scanning, showing an absorption peak in the 400-500 nm range. Optimization of temperature, time, pH, concentration of copper sulfate pentahydrate, and reactant mixing ratios was performed to achieve the most effective CuNPs production. The adsorption of organic sulfide groups, the main contaminants in gas cylinder sediments, onto the CuNPs surface was carried out using column chromatography and surface adsorption techniques.

The optimal conditions for CuNPs synthesis were 1 mM copper sulfate pentahydrate, 70 °C, pH 9, reaction time of 60 minutes, and the ratio of extract to Copper Sulfate pentahydrate was observed at 20:80 mL. The CuNPs exhibited a high adsorption rate (90%) for organic sulfide groups, effectively removing these contaminants from gas cylinder sediments.

The large surface area of CuNPs enabled efficient separation, providing a green, rapid, and environmentally friendly solution for treating hazardous deposits in domestic gas cylinders, making them safe for disposal or reuse.