A review on the effectiveness of nanocomposites for the treatment and recovery of oil spill

Optimization of isotropic MoS2/PES membranes for efficient treatment of industrial oily wastewater

Elimination of tiny oil droplets nearly miscible with wastewater can be realized using membrane technology through ultrafiltration. The novelty of this work was to blend different phases of molybdenum disulfide (MoS2) in isotropic polyethersulfone (PES). We prepared isotropic PES membranes by optimizing nonsolvent vapour-induced phase separation (VIPS). Membranes were blended with MoS2 nanosheets of different phases to promote separation performance and antifouling resistance. FE-SEM revealed the flower-like surface morphology of MoS2 nanosheets. HR-TEM of MoS2 revealed 2H domains in the monolayer, flakes of a few layers and a d-spacing of 0.22 nm. Raman spectroscopy could be used to distinguish mixed-phase MoS2 from single-phase MoS2. Isotropic PES membranes modified with 70% 1T/2H MoS2 had a significantly high permeance to pure water (6911 kg m-2 h bar). The same membrane possessed a high efficiency of oil rejection of 98.78%, 97.85%, 99.83% for emulsions of industrial crude oil at 100, 1000 and 10 000 mg L-1, respectively. Removal of oil droplets from wastewater was dominated by a mechanism based on size exclusion. Isotropic PES modified with 2H MoS2 possessed superior oleophilicity, which resulted in low rejection of crude oil. Modified membranes showed excellent fouling resistance for three successive filtration cycles, as evidenced by enhanced antifouling parameters. Our study reveals how the phase composition of MoS2 nanosheets can significantly affect the performance of isotropic PES membranes during the ultrafiltration of oily wastewater.

3D Oleophilic Sorbent Films Based on Recycled Low-Density Polyethylene

Recycling low-end, one-time-use plastics-such as low-density polyethylene (LDPE)-is of paramount importance to combat plastic pollution and promote sustainability in the modern green economy. This study valorizes LDPE waste by transforming it into 3D oleophilic swellable thin films through a process involving dissolution, phase separation, and extraction. These films are subsequently layered using a customized polypropylene (PP) based nonwoven fabric separator and securely sealed in a zigzag pattern. The zigzag-shaped seal enhances the adhesion of pollutants to the sorbent by providing wire curvatures that increase retention time and uptake capacity. As a result, the sorbent exhibits impressive oil uptake capacities, with immediate and equilibrium values of 120 g/g and 85 g/g, respectively. Notably, the as-prepared sorbent demonstrates low water retention and high selectivity for oil, outperforming commercially available oil sorbents. The unique design involving a 3D-film structure, superposed films, and a zigzag-shaped seal offers a sustainable and value-added solution to the issues of LDPE waste and oil spills on water surfaces.

Magnetic biopolymers' nanocomposites from chitosan, lignin and phycosynthesized iron nanoparticles to remediate water from polluting oil

Targeting the remediation of oil pollution in water, the construction of super magnetic adsorbent nanocomposites (NCs) was achieved using the nanoparticles of chitosan (Cht), lignin (Lg) and phycosynthesized iron nanoparticles (Fe MNPs) using Gelidium amansii extract. The syntheses and conjugations of nanomaterials were authenticated via infrared spectral analysis and the structural physiognomies of them were appraised via electron microscopy and zeta analysis. The Lg NPs, Cht NPs, Fe MNPs and their composites (Lg/Cht MNCs) had mean particles' sizes of 42.3, 76.4, 14.2 and 108.3 nm, and were charged with - 32.7, + 41.2, + 28.4 and +37.5 mV, respectively. The magnetometer revealed the high magnetic properties of both Fe MNPs and Lg/Cht MNCs; the maximum swelling of Lg/Cht NPs (46.3 %), and Lg/Cht MNPs (33.8 %) was detected after 175 min. The diesel oil adsorption experiments with Lg/Cht MNPs, using batch adsorption practices, revealed the powerful potentiality of magnetic NCs to remove oil pollution in water; the maximum adsorption capacity (qt) was achieved with the conditions of pH = 7.5, adsorption period = 90 min and adsorbent dose = 200 mg/L. The magnetic Lg/Cht MNCs exhibited excellent recovery/reusability attributes for five adsorption cycles; the qt differences were negligible after the entire oil-adsorption cycles, with oil removal of >90 %. The innovative fabricated Lg/Cht MNCs could provide an effectual, sustainable and eco-friendly approach for the removal of pollutant oil in water resources.

Applications of bubble curtains in marine oil spill containment: Hydrodynamic characteristics, applications, and future perspectives

Although the marine oil spill pollution issue does not bring us to flock in droves as the new emerging oceanic techniques like wave energy converters, remote operated vehicle (ROV), blue ammonia and green hydrogen, the huge pollution risks of the marine oil spills caused by man-made intentional discharge, old equipment, accidental leakage, war and other aspects should arouse our sufficient attention and concern. As the primary countermeasure of emergency response to a marine oil spill, rapid & efficient oil containment is crucial to limit the pollution scope and the subsequent recovery and treatment. Here, we summarized the existing investigations on oil-spill containment with a marked emphasis on the applications of bubble curtains and their working mechanisms. The critical research progress and trends about the remediation techniques and the application of bubble curtains in marine environments were briefly introduced. The article thoroughly analyzed the basic working mechanism of the bubble curtains in oil spill containment, the technical difficulties of the existing methods, the potential application prospects of coupling with the traditional oil containment booms and the critical scientific problems to be studied in the future. Regarding the issues involving insufficient oil retention performance and inconvenient deployment of the existing traditional oil boom under complex and variable sea conditions, the performance and structural optimization of bubble curtain enhanced oil containment boom will get the top priority in developing the next-generation oil containment techniques.