NOPR Collection:

Studies on chlorine demand and its decay kinetics on the waters of Kali river around Kaiga project area

Mon, 01 Jan 1996 00:00:00 GMT

Title: Studies on chlorine demand and its decay kinetics on the waters of Kali river around Kaiga project area Authors: Bhat, D Krishna; Prakash, T R; Gowda, B Thimme; Sherigara, B S; Khader, A M A Abstract: Chlorination studies have been undertaken on the waters of Kali river to be used as coolant for the nuclear power plant coming up at Kaiga. The study revealed significant seasonal variations in chlorine demand, ranging from 0.5 to 1.3 ppm (3 ppm dose, 30 min contact time) with a total consumption of 5 ppm (10 ppm dose, 48 h contact time). Further, faster first phase of the reaction indicated the presence of readily oxidisable organic and inorganic impurities in the waters, and accounts for the major part of the chlorine demand. The study also shows high correlation of chlorine demand with chlorophyll 'a', suspended matter, turbidity and other inorganic impurities. Page(s): 58-60

Adsorption of Pb(II) on polyacrylamide grafted tin(IV) oxide gel from aqueous solution

Mon, 01 Jan 1996 00:00:00 GMT

Title: Adsorption of Pb(II) on polyacrylamide grafted tin(IV) oxide gel from aqueous solution Authors: Shubha, K P; Anirudhan, T S Abstract: Polyacrylamide grafted hydrous tin(IV)oxide gel has been studied as a sorbent for removal of Pb(II) from aqueous solutions. Effects of contact time, initial concentration, pH and temperature have been studied. The adsorption follows first order kinetics. The uptake is maximum around pH 5.5 and it has been explained on the basis of the surface complexation involving H⁺ exchange. The adsorption isotherms of Pb(II) were found to follow the Langmuir adsorption model. The adsorption rate constants and thermodynamical parameters were also presented to predict the nature of adsorption. The spent adsorbent can be regenerated and reused by acid treatment. Page(s): 55-57

Removal of Hg(II) from aqueous solution by sorption on polymerised saw dust

Mon, 01 Jan 1996 00:00:00 GMT

Title: Removal of Hg(II) from aqueous solution by sorption on polymerised saw dust Authors: Raji, C; Anirudhan, T S Abstract: The ability of polymerised saw dust to adsorb Hg(II) from water has been carried out. The per cent of Hg(II)adsorbed increased with decrease in initial concentration of Hg(ll), increase in adsorbent dosage and temperature. Maximum accumulation was noted within 4 h and maximum removal (94%) was recorded below 10 mg/L of Hg(II).The process follows a first order rate kinetics with diffusion controlled nature and the data fits the Langmuir adsorption isotherm. Sorbent is effective for the quantitative removal of Hg(II)over the pH range 3.5-8.5. Adsorption rate constants, and thermodynamic parameters were also presented to predict the nature of adsorption. Extraction studies confirmed that most Hg(II)could be released by exposure to 1 MHCl or chelating agent (0.1 M EDTA). Page(s): 49-54

Effects of time and temperature on the mild steel corrosion inhibition by molybdate and nitrite

Mon, 01 Jan 1996 00:00:00 GMT

Title: Effects of time and temperature on the mild steel corrosion inhibition by molybdate and nitrite Authors: Mustafa, C M; Rahman, A K M Obaydur; Begum, D A Abstract: An investigation has been conducted to find out the effect of soaking time and temperature on the Corrosion inhibition of mild steel by sodium molybdate and sodium nitrite in simulated cooling water (SCW). Increase of soaking time increases corrosion rate of the mild steel in SCW. However, when sodium molybdate and sodium nitrite are present corrosion rate decreases or per cent inhibition efficiency (% IE) increases with the soaking time. High concentration of inhibitors or stirring of the solution results in the attainment of the corrosion rate to the constant low value at a short soaking period. Molybdate loses its inhibition capacity comparatively rapidly than nitrite with the rise of temperature, and none of them alone is effective at the increased temperature of SCW. When these two inhibitors are used combinedly effective corrosion inhibition of mild steel is obtained up to 55°C temperature of SCW. Page(s): 44-48