NOPR Collection:

Louis Paul Cailletet—The liquefaction of the permanent gases

Sat, 01 Mar 2003 00:00:00 GMT

Title: Louis Paul Cailletet—The liquefaction of the permanent gases Authors: Wisniak, Jaime Abstract: To Louis Paul Cailletet (1831-1913) we owe the realization of the liquefaction of permanent gases using a free expansion process. A brilliant analysis of an experimental mishap led him to achieve this possibility. The priority or oxygen liquefaction was and continues to be a matter of discuss ion. The life and scientific work of Cailletet are described together with details about the priority polemic. Page(s): 223-236

Cashewnut sheath carbon: A new sorbent for defluoridation of water

Sat, 01 Mar 2003 00:00:00 GMT

Title: Cashewnut sheath carbon: A new sorbent for defluoridation of water Authors: Sivabalan, R; Rengaraj, S; Arabindoo, Banumathi; Murugesan, V Abstract: Cashewnut sheath, an agricultural waste discarded largely in India is identified for the preparation of an effective sorbent for fluoride removal. Experiments were conducted for the sorption of fluoride from aqueous solution using activated carbon from cashewnut sheath (CSC) in two phases, namely, batch studies and column studies. The influence of pH, adsorbent dose, particle size and contact time was investigated in batch studies. The adsorption process follows Freundlich adsorption isotherm. Continuous flow experiments in fixed bed columns packed with activated carbon were carried out in order to assess the feasibility of this for field applications. The carbon bed after exhaustion was regenerated with 0.1N hydrochloric acid. The influence of initial concentration of fluoride ion, flow rate, particle size and concentration of the regenerant on the performance of the column was studied. Comparative study was conducted with commercially available carbon impregnated with 2% aluminium sulphate solution. The results revealed that CSC is found to be active and efficient for fluoride removal. Page(s): 217-222

Removal of basic dye from industrial wastewater by adsorption

Sat, 01 Mar 2003 00:00:00 GMT

Title: Removal of basic dye from industrial wastewater by adsorption Authors: Singh, Arvind K; Tiwari, Prem N Abstract: For proper understanding, the process of removal of solute dye by adsorption and to reveal the manner in which this adsorption process can be adopted for removal of the solute material from the solution, the study of isotherm, kinetics and thermodynamic parameters is of paramount importance, The growth of adsorption with time is function of the initial concentration, temperature and pH of the system. The kinetics of adsorption was found to be of first order with intra-particle diffusion at the rate-controlling step. The values of different thermodynamic properties such as ΔG⁰, ΔH⁰ and ΔS⁰ indicate that the process is spontaneous, feasible and exothermic in nature. The adsorption process satisfies Langmuir isotherm. Page(s): 211-216

Adsorption performance of Zr-pillared montmorillonite for the removal of organic pollutants from aqueous phase

Sat, 01 Mar 2003 00:00:00 GMT

Title: Adsorption performance of Zr-pillared montmorillonite for the removal of organic pollutants from aqueous phase Authors: Vinod, V P; Varghese, Sumol; Anirudhan, T S Abstract: This study examined the effectiveness of Zr-pillared Na-rich montmorillonite (PILC) in removing humic acid (HA) and tannic acid (TA) from aqueous solutions by adsorption. Batch experiments were conducted to evaluate the pH effects, the kinetics, temperature effects and sorption isotherm on the HA and TA adsorption onto PILC. The research demonstrated that the PILC could sufficiently remove HA and TA from aqueous solutions. The most effective pH range was found to be 3.0 to 4.0 for both HA and TA. The kinetic studies showed that an equilibrium time of 6 h was needed for the adsorption of HA and TA on PILC and adsorption rates could he described by a first order Lagergren equation. The adsorption of HA and TA was found to increase with ionic strength due to the compression of diffuse double layer. The equilibrium isotherm data for both HA and TA fitted Langmuir isotherm model and based on Langmuir constants, the PILC had a greater adsorption capacity for HA than for TA. The isosteric heats of the adsorption process were determined at various surface coverages of the adsorbent. The thermodynamic parameters such as change in free energy (ΔG^o), enthalpy (ΔH^o), and entropy (ΔS^o) were derived to predict the nature of adsorption. Sheindrof-Rebhun-Sheintuch isotherm model was used to study the competitive interaction for the adsorption of single component from mixture by PILC. About 91.4 and 94.8% of HA and TA can be recovered from the spent adsorbent by controlling the pH at 11.0. Page(s): 201-210