Optimization of Silver Nanoparticle Separation Method from Drilling Waste Matrices

Significant amounts of produced water, spent drilling fluid, and drill cuttings, which differ in composition and characteristics in each drilling operation, are generated in the oil and gas industry. Moreover, the oil and gas industry faces many technological development challenges to guarantee a safe and clean environment and to meet strict environmental standards in the field of processing and disposal of drilling waste. Due to increasing application of nanomaterials in the oil and gas industry, drilling wastes may also contain nanometer-scale materials. It is therefore necessary to characterize drilling waste in terms of nanomaterial content and to optimize effective methods for their determination, including a key separation step. The purpose of this study is to select the appropriate method of separation and pre-concentration of silver nanoparticles (AgNPs) from drilling wastewater samples and to determine their size distribution along with the state of aggregation using single-particle inductively coupled plasma mass spectrometry (spICP-MS). Two AgNP separation methods were compared: centrifugation and cloud point extraction. The first known use of spICP-MS for drilling waste matrices following mentioned separation methods is presented.