A novel sustained release and scale inhibition functional microsphere

Long life-time anti-scaling is one key problem in the oilfield extraction process. Encapsulating the scale inhibitor into microspheres is an effective approach to achieve this effect. Ethylene diamine tetra methylene phosphonic acid sodium (EDTMPS), a scale inhibitor in salt form and with high water-solubility, was successfully encapsulated into polymethyl methacrylate (PMMA) microspheres by the S/O/W solvent evaporation method. The influence of synthesis various parameters on the morphology and particle size was investigated. Release and scale inhibition behaviors of functional microspheres were studied, respectively. Results indicated that the functional microspheres with a regular spherical shape and good dispersibility were obtained. The microspheres possessed encapsulation efficiency exceeding 88% and ideal sustained-release properties (up to 120 hours) ensuring sustainable scale inhibition. The realization of long life-time anti-scaling was attributed to (1) EDTMPS’s sustained-release and (2) the combined effect of chelation and lattice distortion. These novel functional microspheres have a promising application prospect in the field of industrial scale inhibition. • A new way to use scale inhibitors, encapsulation of scale inhibitors, was provided. • The encapsulation efficiency of PMMA/EDTMPS microspheres is up to 88.16%. • The microsphereization of EDTMPS achieves its sustained release effect. • Functional microspheres show good long life-time scale inhibition performance.