Chitosan-Based biogels: A potential approach to trap and bioremediate naphthalene
| Autor: | Louis A. Colaruotolo, Athanasios Paschos, Alejandro G. Marangoni, Erica Pensini, Srdjan Malicevic, Maria G. Corradini, Kristine Lamont, Klaudine M. Estepa, Loong-Tak Lim |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Aqueous solution
Chemistry technology industry and agriculture macromolecular substances 02 engineering and technology equipment and supplies 010402 general chemistry 021001 nanoscience & nanotechnology Calcium stearate 01 natural sciences 6. Clean water 0104 chemical sciences Chitosan chemistry.chemical_compound Colloid and Surface Chemistry Pulmonary surfactant Phase (matter) Emulsion Sodium citrate 0210 nano-technology Naphthalene Nuclear chemistry |
| Zdroj: | Colloids and Surfaces A: Physicochemical and Engineering Aspects. 605:125374 |
| ISSN: | 0927-7757 |
| Popis: | Pseudomonas sp. bacteria were incorporated into a double emulsion system (water in oil in water, W/O/W), which can be injected in the subsurface to trap and biotreat naphthalene. The outermost phase of the W/O/W emulsion was an aqueous solution of chitosan (1.65 wt.%). Naphthalene could be dispersed in the aqueous chitosan phase of W/O/W emulsions. Two separate primary water in oil (W/O) emulsions were emulsified in chitosan, using Tween 20 as emulsifier. W/O emulsions were prepared with canola oil (containing ethylcellulose and calcium stearate as emulsifiers), and aqueous solutions of either Pseudomonas sp. in minimal broth or sodium citrate (crosslinker). The formation of W/O/W double emulsions was verified with optical and confocal microscopy. Without addition of triggers able to induce gelation on demand, W/O/W emulsions were stable and mainly viscous under shear. The shear elastic modulus (G’ = 1.90 ± 0.39 Pa) and the shear viscous modulus (G” = 5.76 ± 0.06 Pa) were low, to facilitate pumping in the subsurface. With addition of the surfactant cocamidopropyl betaine, W/O/W emulsions were destabilized on demand, thereby releasing citrate (crosslinker) and Pseudomonas sp. in the chitosan phase, where naphthalene was dispersed. Mixing chitosan with citrate led to its gelation, trapping naphthalene. Mixing naphthalene with Pseudomonas sp. led to its bioremediation. Gelation was demonstrated by the increase in the viscoelastic moduli, with G’ = 111.02 ± 1.67 Pa > G” = 8.66 ± 0.10 Pa. With naphthalene, Pseudomonas sp. survival in gelled chitosan was confirmed by plating bacteria sampled from the gel. Without naphthalene, Pseudomonas sp. did not survive in chitosan. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect