Novel dispersant based on the synergy of nickel hydroxide and sulfonated lignin for applications in oil spill remediation

Abstract

Chemical dispersants are a controversial solution for oil spill remediation, and the potential toxicity of chemical surfactants to the marine ecology has prompted much research for eco-friendly dispersants with superior dispersing ability. Herein, an efficient Pickering emulsifier was prepared on the basis of the synergistic effect of sulfonated lignin (SL) and nickel hydroxide (Ni(OH)2) micron particles. The interaction of SL and Ni(OH)2 particles was characterized by the contact angle, shear viscosity and Zeta potential measurements. Confocal fluorescence microscopy and optical microscopy images revealed the oil droplet structure. The average emulsion droplet size and emulsification index were investigated. These results indicate that the addition of SL has a synergistic stabilizing effect in high salinity seawater. Here, Ni(OH)2 particles alone are not an efficient emulsifier in seawater because of the strong flocculation caused by high salinity. The adsorption of Ni(OH)2 particles by SL changed their contact angle and benefitted their adsorption at the oil-seawater interface, providing a solid barrier to avoid droplet coalescence, and the stable O/W emulsion exhibited great stability, smaller droplet size and larger oil-water interface area, which facilitated the subsequent natural degradation of crude oil. Therefore, this may be an environmentally friendly and harmless new method for SL and Ni(OH)2 particles to deal with marine oil spill problems.