Ultrasonic bubbles on the solid surface of various sonochemical devices largely affect signal resolution due to the serious reflection/scattering of sound waves. The Laplace pressure of the cavitation bubble can be tuned by constructing an ultrathin hydrophilic layer, which leads to the solvation or pinching off of the bubbles from the surface. In this article, we successfully coated a polydopamine polymer layer on the high-density polyethylene (HDPE) surface. The formed hydrophilic layer with a contact angle of less than 45° almost completely eliminates the bubbles in both water and 32.5 vol % diesel exhaust fluid solutions upon sonication, which results in the operation of the piezoelectric sensor over 500 h, while the sensor with pure HDPE only ran for less than 2 h. Further, the coated sensors showed high stability under the temperatures of 60–80 °C. An improved mechanical property was confirmed via abrasion test, enabling long-term stability in harsh environments, including acidic urine and ultrasonic agitation. The acoustic bubble suppression via the hydrophilic polymer coating on HDPE surface displays broad applications, particularly with acoustic sensors, sonobuoys, and nondestructive surface detection in sonochemistry.
Acoustic aeration on a sonochemical surface could have a major impact on sensitivity because of the serious reflection/scattering of sound waves. Recently, we found that the trapped air in the crevices can be reduced by covering the surface with a hydrophilic coating, thus preventing the bubble formation upon ultrasound agitation. Here, we developed an epoxy-based hybrid polymer coating that shows greatly enhanced mechanical adhesion on a high-density polyethylene (HDPE) surface. The strong bonding of C−O−C and the benzene ring as the backbone ensures excellent mechanical strength, and the hydrophilic polar groups of −OH/−NH 2 on dopamine display bubble suppression. The existing −OH groups in the cross-linked matrix, which is constructed by adding the monomer PEGMA and cross-linker PEGDA, form a strong chemical bond with the HDPE surface via dehydration, which largely enhanced the adhesion force. The coated HDPE surface maintained a low contact angle of less than 45°, which is the critical angle for avoiding bubbles, after a long period period of abrasion cycling of 160 times under 9.8 kPa pressure. The coated HDPE surface displayed excellent bubble removal performance under ultrasound agitation from room temperature to 60 °C. The strengthened mechanical adhesion of the epoxy-based hydrophilic coating displays extensive applications on a variety of surfaces for acoustic bubble removal.
Hydrogel-immobilized lysozyme for antibacterial membrane modification.
Lead is one of the most toxic heavy metals in water systems which poses critical effects on human health. To meet the 10 ppb limit in drinking water recommended by the World Health Organization, a highly efficient adsorbent with extremely lowconcentration removal capability is needed. Herein, we develop a hybrid composite adsorbent βCD-AC-CaBent that is composed of βcyclodextrin, activated carbon, and calcium-enhanced bentonite clay via a chemical method. The enlarged surface area of 41.56 m 2 /g and increased negative charge of −45.04 mV greatly improved the attraction of Pb 2+ to the porous surface, while the large amount of active Ca 2+ sites further increased the ion-exchange capacity. By varying the initial Pb 2+ concentration, pH value, and contact time, the adsorbent's lead removal capacity was studied in batch tests, whose results were fitted with pseudo-first-order, pseudo-second-order, and intraparticle diffusion kinetic models and Langmuir/Freundlich isotherms. In parallel, breakthrough curves with Pb 2+ concentrations from 12 to 100 mg L −1 , flow rates from 10 to 100 mL min −1 , and bed heights from 1.2 to 3.2 cm were obtained in a continuous fixed-bed column, which were fitted with Thomas, Yoon−Nelson, and Bohart−Adam models, respectively. The hybrid adsorbent displayed excellent removal efficiency after regeneration, which indicates its promising potential in sustainable applications. The results showed that the capacities of 174.5 mg g −1 at a dosage of 1.0 g L −1 and 434.78 mg g −1 at a dosage of 0.25 g L −1 were, respectively, achieved within about 60 min, which are higher than those of pure bentonite and most of the commercial adsorbents. In column tests, an adsorption capacity of up to 39.78 mg g −1 was obtained. More importantly, the removal uptake capacity of 10.5 mg g −1 at 0.5 ppm Pb 2+ concentration and 4.3 mg g −1 at 50 ppb Pb 2+ concentration was achieved upon treatment of 75 L of water. As high as 100% Pb 2+ ions were removed at the beginning and still 70% Pb 2+ ions were removed upon saturation in industrial wastewater. The current results suggest a new hybrid adsorbent that can deliver a high lead removal capacity in water under differential conditions especially with extremely low-ion concentrations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.