RESUMO
In this work, a comparative analysis of Fenton, Fe2+/NaOCl and Fe2+/(NH4)2S2O8 assisted advanced oxidation processes was carried out to study its efficacy in enhancing tannery chemical sludge dewaterability. Experimental results showed that, after conditioning of sludge at optimum pH, oxidant and catalyst dosage, capillary suction time (CST) was decreased by 75 ± 5 % and moisture content of sludge cake (M.Ccake) was reduced to 74 ± 2 % for all processes at 10 min reaction time. Among the three processes, Fe2+/(NH4)2S2O8 process was noted to have larger impact on the breakdown of sludge cells, which is reflected in terms of its highest amount of total organic carbon, protein and total dissolved solids present in the separated sludge fractions. In addition, Fe2+/(NH4)2S2O8 process was also observed to leach out largest fraction say 73.3 % of chromium present in the raw sludge into the treated sludge filtrate. The investigation carried out through zeta potential and scanning electron microscopy reveals the role of a two-step mechanism, namely oxidation followed by coagulation in enhancing the sludge dewaterability. Further studies on the possibility of utilizing dried treated sludge as biomass fuel could be carried out.
RESUMO
The dermal penetration of bisphenol-A (BPA) from thermal papers into the human skin is a matter of major health concern due to its extensive use in developing countries like India, one of its largest users in the world. Bisphenol A is widely used in the manufacture of many consumer goods like polycarbonate water bottles, baby bottles, food containers, home appliances, thermal papers used in billing and tickets, the inner lining of food cans, etc. BPA can be easily adsorbed into the blood rapidly. The integration of optical tweezers with Raman spectroscopic techniques has realized avenues for interpreting single cell investigations. In the present work, the impact of BPA from thermal papers on individual human erythrocytes (red blood cells) has been investigated using micro-Raman spectroscopy. Significant intensity variations were noticed for hemoglobin oxygenation markers in the Raman spectra of red blood cells (RBCs). Raman spectral variations supporting RBC hemoglobin depletion were also found in the presence of BPA. Evident morphological changes are also observed in RBCs due to BPA in vitro exposures, which ultimately lead to cell bursting at higher concentrations.
