Transparent CaF₂ surface crystallized CaO–2B₂O₃ glass possessing efficient photocatalytic and antibacterial properties

Abstract

This study aims to fabricate surface crystallized transparent calcium borate glass (CaO–2B2O3) for photocatalytic and antibacterial applications. The CaO–2B2O3 glass was fabricated by using the conventional melt‐quenching technique. Instead of using traditional high temperature and longer soaking time heat‐treatment, the acid etching method was adopted to get surface crystallization. Surface etching of as‐quenched glass was performed at room temperature by using three different concentrations of hydrogen fluoride in order to attain the different amount of calcium fluoride crystals at the surface. The characterization of surface crystallized glass was performed with an X‐ray diffraction pattern and scanning electron microscope‐EDS mapping system. Sufficient transparency (65%) was retained even at highest crystallization of glass surface. Surface crystallization with CaF2 induces hydrophilicity and photocatalytic character in glasses which was evaluated with contact angle measurements and smart resazurin (Rz) ink test. Around 68% of methylene blue (MB) dye degradation was also displayed by the crystallized glass. Crystallized glasses portrayed good antibacterial property against Escherichia coli (gram‐negative bacteria). Ninety‐nine per cent of bacterial depletion was recorded in 3 hours exposure time with surface crystallized glass without any external intervention. Interesting morphological changes were observed in bacterial shape and physical appearance under field emission scanning electron microscope after exposure to crystallized glasses.

Solar/visible light photocatalytic dye degradation using BaTi1−xFexO3 ceramics

“…However, their low photocatalytic efficiency resulted in the tailoring of these materials. Many other methods, like bandgap tuning, doping of transition metals, and implantation of anions, are utilized to enhance photocatalytic activities 18–20 . Many multiferroic materials can be in the same phase having ferromagnetic and ferroelectric, which can be used for multifunctional applications.…”

“…Many other methods, like bandgap tuning, doping of transition metals, and implantation of anions, are utilized to enhance photocatalytic activities. [18][19][20] Many multiferroic materials can be in the same phase having ferromagnetic and ferroelectric, which can be used for multifunctional applications. Typical multiferroic materials have partially filled d-orbitals, leading to the existence of magnetic property, whereas non-centrosymmetric structure will result in spontaneous electric polarization responsible for ferroelectricity.…”

Transparent ferroelectric glass–ceramics for wastewater treatment by piezocatalysis

“…These cavity bubbles generally contain entrapped gases and surrounding water vapors 47 . This continuous phenomena of the formation/growth/collapsation of bubbles lead to the formation of local hot spots with temperature of 4000-5000 K and in addition to this, a shock wave having~10 8 Pa peak pressure releases 19,47 . These local hot spots decompose the contents of bubbles into free˙OH radical species using thermolysis (sonolysis) process 47,48 .…”

“…During this, some of these reacts with OH − ions and adsorbed O 2 and then generate˙OH and˙O À 2 as shown in Eqs. (5)- (8). These radicals further decompose MB dye into degradation products.…”

“…The improved optical, luminescence properties, mechanical strength, physical, chemical stability, bioactivity, corrosion strength, and temperature resistance were noticed due to crystalline phase embedded in glassy matrix [4][5][6] . Similarly, some unique properties such as photocatalysis [7][8][9] , antibacterial activity [7][8][9] and cancer treatment capability through hypherthermia treatment 10 , etc., are also induced through selected crystalline phase in glass-ceramics.…”