SARS-CoV-2 removal with a polyurethane foam composite.

The pandemic of COVID-19 (SARS-CoV-2 disease) has been causing unprecedented health and economic impacts, alerting the world to the importance of basic sanitation and existing social inequalities. The risk of the spread and appearance of new diseases highlights the need for the removal of these pathogens through efficient techniques and materials. This study aimed to develop a polyurethane (PU) biofoam filled with dregs waste (leftover from the pulp and paper industry) for removal SARS-CoV-2 from the water. The biofoam was prepared by the free expansion method with the incorporation of 5wt% of dregs as a filler. For the removal assays, the all materials and its isolated phases were incubated for 24 h with an inactivated SARS-CoV-2 viral suspension. Then, the RNA was extracted and the viral load was quantified using the quantitative reverse transcription (RT-qPCR) technique. The biofoam (polyurethane/dregs) reached a great removal percentage of 91.55%, whereas the isolated dregs waste was 99.03%, commercial activated carbon was 99.64%, commercial activated carbon/polyurethane was 99.30%, and neat PU foam reached was 99.96% for this same property and without statistical difference. Those new materials endowed with low cost and high removal efficiency of SARS-CoV-2 as alternatives to conventional adsorbents.

Chitosan-coated sand and its application in a fixed-bed column to remove dyes in simple, binary, and real systems.

Adsorption of tartrazine yellow food dye, in a fixed-bed column, was carried out using a single system, a binary system (in the presence of sunset yellow food dye), and in a real effluent provides from an ice cream industry. Chitosan was used to coat sand particles by the dip-coating technique, and these particles were applied in fixed-bed adsorption. The assays were performed in flow rates of 3 mL min-1 and 5 mL min-1. The best performance was reached at 3 mL min-1. In this flow rate, for single and binary systems, the breakthrough time was 95 min and 65 min, and the maximum capacity of the column was around 595 mg g-1 and 497 mg g-1, respectively. In the assay conducted with the real effluent, the breakthrough time was 10 min, and the maximum adsorption capacity of the column was reduced to 191 mg g-1 for tartrazine dye. The dynamic models of Thomas and Yoon-Nelson were used, and both were suitable to represent the breakthrough curves.