Ceramic water filters (CWFs) are widely utilized as a low-cost and effective point-of-use (POU) drinking water treatment technology in developing countries for the removal of pathogenic microorganisms. However, CWFs generally showed low removal efficiency for waterborne virus which poses a high health risk. In this study, we employed a novel lanthanum (La) coating for CWFs to enhance viral removal. Compared to the negligible viral removal of raw CWFs (<0.2 log), CWFs with La coating prepared at 600 °C effectively treated ∼10,000 pore volumes of virus-contaminated water without the detection of any infective virus in the effluent (∼5 log removal). Its equivalent treatment volume is expected to surpass the treated volume of a commercial CWF in the whole service lifespan. The characterization of La-coated ceramic, combined with analysis of the extended Derjaguin–Landau–Verwey–Overbeek energy profiles and inactivation kinetic tests, indicated that the enhanced viral removal by La-coated CWFs may be attributed to the increased attachment of virus onto the filter surface due to the reduction of the repulsive energy barrier and the presence of secondary energy minimum, as well as the inactivation nature of La-coated ceramic. These processes minimized the risk of remobilization and release of infective virus from ceramic filters, further confirming by the desorption test. Furthermore, the viral genome and biospectroscopic analysis suggested that both genome damage and protein capsid conformational changes caused the viral inactivation by La-coated ceramic. Our finding showed that La-coated CWFs may represent a promising practical POU treatment solution for viral removal particularly suited for developing countries. The results also provided fundamental insights into the interactions between La species and virions, which may advance the research on La application for water treatment.

Low-cost and efficient ceramic water filters for point-of-use (POU) water treatment are a sustainable solution for low-income areas suffering from microbial contamination in drinking water sources. In this work, a novel coating of lanthanum (La) on a ceramic filter prepared using paper and leaf fibers as combustible materials was developed for enhanced bacterial removal. Results from filtration experiments showed that the La coating thermally treated at 400 °C led to the highest bacterial removal of >6 log reduction value, which was >2 and ∼4 orders of magnitude better than those of the filters treated with higher La-coating temperatures and the uncoated filters, respectively. Additionally, the La-coated (400 °C) filters made using recycled paper can efficiently treat ∼60,000 pore volumes of bacterial contaminated water to meet the drinking water standard (<0 CFU/100 mL) in long-term filtration tests, extending the service life span of ceramic filters. The characterization of La-coated filters, calculation of extended Derjaguin− Landau−Verwey−Overbeek energy profiles, as well as biospectroscopic analysis showed that the enhanced bacterial removal by Lacoated filters may be attributed to (1) the formation of microscopic pores with sizes favorable for bacterial removal through straining, (2) the favorable attachment and immobilization condition due to the presence of a significant attractive secondary energy minimum, and (3) the interaction of the La coating and bacterial cells likely through bonding of La and the phosphate group in the cell structure. Our findings suggested that La-coated ceramic filters made of readily available and sustainable materials could provide a low-cost and effective POU treatment solution for bacterial removal, which can be particularly well suited for the developing countries.

We demonstrate the fabricating method for Yb 3+ -doped silica glass and double-cladding large mode area photonic crystal fiber (LMA PCF) based on laser sintering technology combined with a liquid phase doping method. The doped material prepared shows the amorphous property and the hydroxyl content is approximately 40 ppm. The attenuation of the fabricated LMA PCF is 14.2 dB m −1 at 976 nm, and the lowest value is 0.25 dB m −1 at 1200 nm. The laser slope efficiency is up to 70.2%.

We report on an ytterbium-doped photonic crystal fiber fabricated by laser sintering technology combined with a solution doping method. This novel fabrication process has never been reported to the best of our knowledge. Together with low non-linearity, this PCF combines the advantages of high pump absorption efficiency and bend-insensitive, which makes this fiber predestinated for the high power fiber laser applications. The fiber laser experiment was conducted with a simple Fabry-Perot cavity to verify the performance of the PCF. A high slope efficiency of ~70.6% was obtained from a 1.5 m-long fiber. During the experiment, no roll over was observed up to the highest power level, which was only limited by the available pump power. The experimental results reveal the enormous output power scaling potential of the PCF.

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