Utilizing L-arginine as an eco-friendly absorbent for hydrogen sulfide mitigation in produced water

The petroleum industry faces a growing need for sustainable treatment of sour produced water to prevent the release of toxic hydrogen sulfide (H₂S), which poses serious environmental and health risks. Capturing and removing H₂S remains a significant economic and environmental challenge, highlighting the importance of advancing effective H₂S mitigation technologies. This work evaluated a green, in house material, L-arginine, at varying concentrations as a novel absorbent for H₂S removal from both deionized water (DIW) and produced water (PW). The compound was thoroughly characterized and its performance benchmarked against a commercial triazine-based scavenger. The assessment emphasized removal efficiency over different concentrations, contact times, and operating temperatures (25 °C and 50 °C). L-arginine substantially increased the pH of both DIW and PW, reaching 10 to 11 in DIW and 9 to 10 in PW. Both L-arginine and triazine achieved exceptional H₂S removal, sustaining 99 to 100%. Notably, even at 0.1 wt% L-arginine reduced H₂S from 990 ppm to ≤ 6 ppm in both water types, while higher concentrations achieved complete removal. Salts in PW (e.g., NaCl, CaCl₂, etc.) had minimal impact on L-arginine's effectiveness, and its performance remained stable at 50 °C, demonstrating resilience to temperature variation. It also showed excellent durability, achieving complete H₂S removal within 2 h and maintaining levels below detection for at least 4 h. Overall, L-arginine emerges as a promising, ecofriendly, and effective alternative absorbent for H₂S removal from produced water that rivals or outperforms commercial treatments. By mitigating H₂S, L-arginine helps reduce environmental hazards. This work represents the first comprehensive comparison of L-arginine's H₂S scavenging performance with a commercial triazine benchmark under varied salinity, temperature, and time conditions.