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Design of Highly Compact and Cost-Effective Water Purification Systems for Promoting Rural and Urban Welfare
Published in Sundergopal Sridhar, Membrane Technology, 2018
B. Govardhan, Y.V.L. Ravikumar, Sankaracharya M. Sutar, Sundergopal Sridhar
To overcome fouling, the membrane should be washed with acid or alkali. Membrane cleaning can be done every alternate day, once a week or every fortnight, depending upon feed water TDS and silt density index (SDI), as per the following protocols which prolong membrane life: Acid wash is to be given with 1% (w/v) citric acid or 1% HCl in tap water for 15 min. in recirculation mode to remove mineral scales and metal precipitates. This is followed by a tap water wash for 5 min. Alkaline wash can be performed by an aqueous solution containing 1% (w/v) of NaOH + 0.5% (w/v) of tetra sodium salt of EDTA + 0.1% (w/v) of the surfactant, sodium lauryl sulphate (SLS), for 15 min. to remove organic foulants. Trisodium phosphate (TSP) can be used in place of NaOH in the alkaline wash step. It may be noted that the efficiency of these washing steps would improve if the acidic and alkaline solutions are prepared in deionized water or RO permeate water, instead of tap water. To prevent biological fouling by fungal growth or blue-green algae, which brings about permanent degradation, the membrane can be preserved safely in 0.5% (w/v) aqueous sodium metabisulphite solution (SMBS) for months together, especially during shutdown. Flushing with 0.5% SMBS once a week when the plant is under continuous operation also helps.
Impact of magnetic field strength generated by Halbach array on hard water for solar applications
Published in International Journal of Ambient Energy, 2022
Ajaj Attar, M. Arulprakasajothi
In boilers, the calcium and magnesium present in hard waters form a hard, adherent scale on the plates (Latva et al. 2016; Sohaili et al. 2016). Inferior heat conductivity of the scale results in more fuel consumption, and the boiler deteriorates rapidly because of the external overheating of the plates. Sodium carbonate hydrolyses to produce free alkali, which causes caustic embrittlement and failure on the boiler plates (Sohaili et al. 2016). Water softening is possible on a small scale by adding ammonia, borax or trisodium phosphate, with sodium carbonate (Mahmoud, Yosra, and Nadiab 2016). Large-scale water softening is done by the addition of enough lime to precipitate the calcium as carbonate and the magnesium as hydroxide, so that sodium carbonate is added to remove the remaining calcium salts (Sohaili et al. 2016).
Tellurium Behavior in the Containment Sump: Dissolution, Redox, and Radiolysis Effects
Published in Nuclear Technology, 2021
Anna-Elina Pasi, Henrik Glänneskog, Mark R. St.-J Foreman, Christian Ekberg
The main components in the sump of a pressurized water reactor in the early stages of an accident are boric acid from both the primary system and containment spray and a base (sodium hydroxide, potassium hydroxide, trisodium phosphate) from pH adjustment, originating either from the refueling water storage tank or placed on the bottom of the containment [trisodium phosphate (TSP)] (Ref. 29). Some plants also use a reducing additive (thiosulfate, hydrazine) in the spray system, which is used to decompose iodine compounds and manage the water chemistry. The pH of the sump is targeted to stay above 7 in accident conditions.29 More precisely, the target pH is generally around 9.3 (Ref. 30). The pH is maintained alkaline with a base in order to keep iodine as a soluble species and thus minimize the possible iodine revolatilization from the sump back into the containment atmosphere. However, the radiolysis and pyrolysis of air and cables produce HCl and HNO3, respectively, which can lower the pH of the sump during the accident.31 In addition, reactions of different FPs, including tellurium,20,32 with organic compounds originating from paint, ion exchange resins, or insulation materials in the sump can lead to more volatile species and increase the source term.33,34
Ethanol production from cassava starch by protoplast fusants of Wickerhamomyces anomalus and Galactomyces candidum
Published in Egyptian Journal of Basic and Applied Sciences, 2020
Tolulope Modupe Adeleye, Sharafadeen Olateju Kareem, Mobolaji O. Bankole, Olusegun Atanda, Abideen I. Adeogun
Chemicals include: absolute ethanol (BDH Chemicals), ethylenediaminetetraacetic acid (EDTA), isopropanol, potassium acetate, proteinase K, sodium chloride, PVP, ammonium sulfate (Sigma Chemical Company, USA.), sodium sulfate, trisodium phosphate, sodium potassium tartrate, and acetic acid. Others include sodium dihydrogen phosphate, sodium hydroxide, calcium chloride, mannitol, potassium chloride, sodium chloride, ammonium sulfate, magnesium sulfate, sorbitol, hydrochloric acid, ribose, xylose, arabinose, rhamnose, glucose, sucrose, lactose, fructose and maltose sugars all obtained from BDH Chemicals, UK., 3,5-dinitrosalicylic acid, polyethylene glycol (PEG, Mw 3350), glycerol, 2-βmercaptoethanol, bromophenol blue, acrylamide, bis-acrylamide, Whatman filter paper grade 1, tris hydrochloric acid ammonium per