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This study focuses on the adsorption of hexavalent chromium (Cr(VI)), a harmful heavy metal, using two types of chlorella-based biochar (biochar pyrolyzed at 200 °C (CB200) and iron chloride (FeCl3)-modified biochar pyrolyzed at 200 °C (FeCB200)), and the testing of their effectiveness for the removal of Cr(VI). The FeCB200 sample exhibited the highest removal efficiency (1 g L−1=66.12±1.01%; 5 g L−1=98.48±0.22%) compared to raw biomass (1 g L−1=54.05±0.00%; 5 g L−1=90.09±0.26%) and CB200 (1 g L−1=51.80±0.78%; 5 g L−1=94.74±0.26%) in 100 mg L−1 Cr(VI) solution. The adsorbents were characterized using various characterization techniques, and adsorption experiments were carried out using varying doses of the adsorbent (1 and 5 g L−1). Pseudo-second-order model provided the best fit for the adsorption kinetics, and Redlich-Peterson model exhibited good fitting for the adsorption isotherm (R2>0.972), although variations were observed depending on the dose. Further, the applicability of FeCB200 was assessed using real wastewater spiked with Cr(VI). Although the presence of organic matter resulted in a reduction in the adsorption effectiveness of FeCB200, the difference was not significant (1 g L−1=54.27±3.19%; 5 g L−1=98.48±0.22%). These results demonstrate the promising potential of FeCl3-modified chlorella-based biochar as a valuable adsorbent for the Cr(VI) removal from water environments. [ABSTRACT FROM AUTHOR]

Monchromatic, low-pressure UV radiation can inactivate Cryptosporidium oocysts and the oocysts do not seem to be capable of repairing the CNA damage. Cryptosporidium is resistant to other forms of disinfection, including chemical disinfection.

Polyaniline (PANI) is a promising conducting polymer for surface modification of TiO2 to achieve extended photoresponse to visible light and increased photocatalytic efficiency. In this study, we report the synthesis of a PANI/TiO2 composite with different weight ratios of PANI, which was subsequently employed for photocatalytic degradation of methylene blue (MB), bisphenol A (BPA), and bacteriophage MS2 under visible-light irradiation. The functional groups, morphology, and light response of the composite were characterized by Fourier-transform infrared spectroscopy, field-emission transmission electron microscopy, and diffuse reflectance UV–visible spectroscopy, respectively. The PANI/TiO2 composite containing 4% by weight ratio of PANI was most suitable for MB degradation, and this photocatalyst was very stable even after repeated use (four cycles). The degradation of BPA and bacteriophage MS2 by PANI/TiO2 composite reached 80% in 360 min and 96.2% in 120 min, respectively, under visible-light irradiation. Therefore, the PANI/TiO2 composite with enhanced visible-light photocatalytic efficiency and stability can be widely used for the degradation of water contaminants. [ABSTRACT FROM AUTHOR]

Results indicate that rapid and extensive reduction of Norwalk and other enteric viruses can be achieved by ozone disinfection of water. Data show more than 3 log(sub)10 reduction in Norwalk, poliovirus 1, and bacteriophage MS2 within 10 seconds of ozone treatment.

In processes of manufacturing semiconductors, reactive by-products (as a form of fine powder, i.e., dust) are deposited in pipes installed on post processing and exhaust systems, potentially involving a considerable explosion risk. In this study, the effectiveness of scrubber methods (e.g., dry scrubber and burn-wet scrubber) to mitigate the risk was evaluated. To this end, three by-products generated from a ZrO 2 atomic layer deposition (ALD) process were collected from semiconductor manufacturers, which were treated with different methods (i.e., no treatment, treatment using dry scrubber, and treatment using burn-wet scrubber), and their characteristics were analyzed and compared. Particle size measurements of the by-products proved that the burn-wet scrubber treatment less decreased their particle size than the dry scrubber treatment. The burn-wet scrubber treatment made the by-product thermally stable, confirmed by thermogravimetric analysis. Fourier-transform infrared spectroscopy of the by-products before and after the scrubber treatments showed that burn-wet scrubbing of the by-product decreases surface functionalities that play a role in explosion. Dust explosion testing proved that robustness of explosion of the untreated by-product is about 7 times higher than the by-product treated with the burn-wet scrubber. Based on the results of this study, it would be suggested that burn-wet scrubber is a useful treatment method to decrease the explosion risks caused by dust by-products generated from ALD in semiconductor manufacturing processes., (Copyright © 2020 Elsevier B.V. All rights reserved.)