Combination of an Asphalt Stabilizer and a Cellulose–Chitosan Composite Aerogel Used for the Separation of Oil–Water Mixtures Containing Asphalt

Abstract

In this paper, cellulose chitosan composite aerogels were prepared through sol–gel and freeze-drying processes. The porous morphology of the aerogels was controlled by adjusting the cellulose concentration. Within a certain range, as the concentration of cellulose increases, the pore diameter of the composite aerogel becomes smaller and the pore structure becomes denser. The cellulose–chitosan composite aerogel can successfully separate the oil–water mixture without asphalt and showed stable filtration performance. The filtration speed is basically unchanged after a slight decrease and can be maintained at about 90% of the initial filtration speed within 30 min. The filtration speed can reach up to 9315 kg·h–1·m–2. When filtering bituminous oil–water mixtures, the filtration rate decreased significantly, with a 50% drop in 30 min. After adding the asphalt stabilizer poly­(styrene-alt-octadecyl maleimide) (SNODMI), which is made in our laboratory, the effect of aerogel filtering the asphalt-containing oil–water mixture is obviously improved, and the downward trend of filtration speed is obviously improved. The combination of SNODMI and cellulose–chitosan has great application potential in the field of asphalt-containing oil–water separation.

Cellulose: A Review of Water Interactions, Applications in Composites, and Water Treatment

“…251−255 Nanocellulose has also been used to control aggregation 256 as well as to tune the porosity of aerogels. 257 Conducting polymers such as poly(pyrrole), polythiophene, and polyaniline are attractive for water treatment due to their high adsorption capacities for metal ions and the ease of synthesis and functionalization. 258,259 However, they tend to aggregate during synthesis, reducing sorptive surface areas.…”

Cellulose–Chitosan Functional Biocomposites

“…To take full advantage of all the distinguished chitosan and cellulose functions, such as appropriate mechanical properties, large accessible surface area and well-defined porosity, high functionality, etc., investigations focus on the development and application of a variety of structures and forms of cellulose–chitosan composites, mainly aerogels [ 77 , 78 , 79 ], foams or sponges [ 80 , 81 ], membranes [ 82 ], hydrogels and films [ 83 ], nanoparticles [ 84 , 85 ], fibres and nanofibers [ 86 , 87 ], etc. Many different approaches and techniques have been applied and studied, including various solubilisation processes, as well as drying techniques for aerogels formation, such as freeze-drying, supercritical conditions, vacuum, ambient pressure, microwaves, etc.…”

Natural polysaccharide-based aerogels and their applications in oil–water separations: a review

“…At the same time, the rough microstructure and the synergistic effect of a large number of hydroxyl and amino groups provide strong hydrophilicity for the aerogel; thus, the water layer formed on the surface of the aerogel has a repulsive force against the oil, and the contact angle of the aerogel to the oil droplet is 160 , which enables oil/seawater separation with high separation efficiency (>99%). Hu et al 217 studied the effect of polysaccharide substrate concentration on the nal aerogel porous structure when preparing cellulose/ chitosan composite aerogels. The report pointed out that the whole aerogel is composed of a cellulose network, and within a certain range, with the increase in the cellulose concentration, the pore size of the composite aerogel becomes smaller and the pore structure becomes denser.…”