21 research outputs found

    A novel technique for detoxification of phenol from wastewater: Nanoparticle Assisted Nano Filtration (NANF)

    Get PDF
    © 2016 Naidu et al. Background: Phenol is one of the most versatile and important organic compound. It is also a growing concern as water pollutants due to its high persistence and toxicity. Removal of Phenol from wastewaters was investigated using a novel nanoparticle adsorption and nanofiltration technique named as Nanoparticle Assisted Nano Filtration (NANF). Methods: The nanoparticle used for NANF study were silver nanoparticles and synthesized to three distinct average particle sizes of 10 nm, 40 nm and 70 nm. The effect of nanoparticle size, their concentrations and their tri and diparticle combinations upon phenol removal were studied. Results: Total surface areas (TSA) for various particle size and concentrations have been calculated and the highest was 4710 × 1012 nm2 for 10 nm particles and 180 ppm concentration while the lowest was for 2461 × 1011 for 70 nm and 60 ppm concentrations. Tri and diparticle studies showed more phenol removal % than that of their individual particles, particularly for using small particles on large membrane pore size and large particles at low concentrations. These results have also been confirmed with COD and toxicity removal studies. Conclusions: The combination of nanoparticles adsorption and nanofiltration results in high phenol removal and mineralization, leading to the conclusion that NANF has very high potential for treating toxic chemical wastewaters

    Ascertaining and Optimizing the Water Footprint and Sludge Management Practice in Steel Industries

    No full text
    Steelmaking is a water-intensive process. The mean water intake against each ton of steel manufactured is ascertained as between 2 and 20 m3. Primarily, the stated requirement is in the form of make-up water to compensate for evaporation and mechanical losses and does not contribute to wastewater generation. Conversely, unit operations, such as rolling, continuous casting, pickling, etc., generate highly complex wastewater rich in polycyclic aromatic hydrocarbons (PAH), cyanide, ammonia, non-consumed acids, benzene, toluene, xylene, oil, grease, etc. Further, the conjugative wastewater contains a high concentration of metallic oxides, toxic elements, oil, nitrogen, and heavy metals such as zinc, nickel, chromium, etc. These contaminants are generally treated and neutralized using physicochemical and membrane-based systems. This also yields hazardous sludge, which is landfilled, thereby incurring an ancillary financial burden. However, sludge can be a frugal source of extracting multi-dimensional benefits. The present review investigated and identified the most water-intensive and wastewater/sludge-contributing unit operations and proposed a preferential combination of treatments to balance efficacy and economy. Further, the various global practices for sludge recycling and management documented in the existing literature are summarized and ranked with the help of the analytic hierarchy process (AHP). The findings revealed concrete making and nutrient recovery as the most- and least-preferred recycling alternatives
    corecore