Abstract
Scallop-shell powder (SSP) heated at high temperature exhibits high pH and broad antimicrobial activity. Bioshell calcium oxide (BiSCaO) is an SSP composed mainly of calcium oxide. It is poorly water-soluble under alkaline conditions and the generated precipitate can plug spray nozzles. The aim of this study was to establish that BiSCaO dispersion caused no significant CaO loss and plugging of spray nozzles, and to evaluate its deodorization and microbicidal abilities and its ability to reduce the concentrations of NO2− and NO3−. BiSCaO dispersions were prepared by mixing various concentrations of BiSCaO suspension, while phosphate compounds such as Na3PO4, Na2HPO4 or NaH2PO4 and the pH, average diameter, zeta potential, and form of the compounds with cryo-SEM were evaluated. We evaluated deodorization using tainted pork meat and microbicidal efficacy using contaminated suspension with normal bacterial flora. The concentration of NO2− and NO3− after mixing BiSCaO dispersion and pure water containing a high proportion of NO2− and NO3− were measured. BiSCaO dispersion formed with Na2HPO4, whose ratio to BiSCaO was 60%, showed a high pH (>12), a small particle diameter (>181 nm) and was stable for seven days. The BiSCaO dispersion showed higher deodorization and microbicidal activities than SSP-Ca(OH)2, which was mainly composed of Ca(OH)2. BiSCaO, but not SSP-Ca(OH)2, could reduce the concentration of NO2− and NO3− by more than 90% within 15 min. We developed a stable BiSCaO dispersion, and it had high deodorization and microbicidal efficacy. These activities of BiSCaO might result from the high pH caused by CaO hydration and a reduction activity causing active radical species.
Highlights
Various metal nanoparticles (MNPs) have been used in diverse fields, ranging from environmental remediation and biomedicine to catalysis, opt-electronic materials, and sensors [1,2]
Flocculation was formed from pH 10.5 to pH 6, and the flocculent completely dissolved to provide a clear solution at pH ≤ 5
Bioshell calcium oxide (BiSCaO)-6 immediately after opening is a polymorphic powder with a wrinkled surface structure (Figure 3a), while BiSCaO-6 placed under high humidity at 37 °C for seven days to prepare BiSCaO-6 exhibited a porous surface structure similar to that of nanoparticle aggregates (Figure 3b). Those observations suggested that hydration reaction on the surface of BiSCaO-6 may lead to the refinement of calcium oxide (CaO) crystals and rift and pore formations, which may promote the production of nanoparticles from microparticles in water dispersion
Summary
Various metal nanoparticles (MNPs) have been used in diverse fields, ranging from environmental remediation and biomedicine to catalysis, opt-electronic materials, and sensors [1,2]. MNPs comprising silver [1,3,4], copper oxide [1,2,5], zinc oxide [1,2,6], titanium oxide [2,7], and calcium oxide (CaO) [8,9]. Calcium oxide produced from limestone (LiMCaO) is an important inorganic compound used in various industries as, for example, an adsorbent, toxic-waste remediation agent, and an alkalization agent. Most scallop shells are considered to be industrial waste, and the shells accumulate on the shores of harvesting districts in
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
