Abstract

Produced water from oil and gas extraction poses a major environmental challenge due to its high boron content and associated risks to ecosystems and human health. Traditional boron removal methods suffer from high costs, limited efficiency, and the generation of secondary pollutants. This study presents a comprehensive assessment of strontium chloride as a precipitating agent in an optimised chemical oxo-precipitation process for removing boron from produced water. Through systematic variation of critical operational parameters, including pH, reagent dosages, and mixing speed, the treatment achieved nearly 85% boron removal under optimal conditions. Toxicity evaluation using Lactuca sativa L. lettuce seeds revealed a 133% increase in the median lethal dose after treatment, demonstrating substantial mitigation of ecological risk. The process embodies key principles of green chemistry by minimising hazardous byproducts, employing safer chemicals, and reducing sludge generation compared with barium-based methods, thereby improving safety for both workers and the environment. Therefore, this methodology directly contributes to the United Nations Sustainable Development Goals by advancing water quality improvement, promoting the reuse of treated water, minimising pollutant discharges, and supporting the protection of terrestrial ecosystems and public health through sustainable innovation.