Papers by Keyword: Langmuir Adsorption Isotherm

Abstract: Advanced concepts for photovoltaic silicon solar cells, especially high-efficiency n-type solar cells, requires appropriate wet cleaning treatment in order to remove metallic contamination prior to high temperature processes like diffusion and passivation [1]. The cost of the cleaning process should be as low as possible that requires an optimized usage of the chemicals by increasing process tank lifetimes and developing dedicated feed and bleed recipes. The just clean enough concept has been developed to fulfil the needs of PV industry to minimize the consumption of chemicals. When the dominant contamination metal is identified in quality and quantity, a dedicated wet chemical cleaning process can be applied to remove the metal concentration from the semiconductor surface under a specified limit with the minimum volume on cleaning solution. The paper describes how to optimize a dedicated wet cleaning process for prominent metal impurities like Fe, Cu, Cr, Ti, Co and Zn. For each metal an exchange volume is determined to develop a feed and bleed recipe. The accumulation of the metal impurities in the process tank is calculated and process tank lifetimes are predicted.

Abstract: Significant amounts of fluorescent light have been discarded every year. Mercury is released into the atmosphere in the recycling process of it, if improperly treated. The adsorption method is used to remove mercury discharged from the recycling step of fluorescent light.We studied the impregnation condition of adsorbent made from sewage sludge. And also adsorption characteristics of mercury were evaluated by impregnated adsorbent.According to our results, the adsorption efficiency of mercury was increased by impregnating adsorbent with chlorine and iodine. The adsorption capacity was described by Langmuir isotherm model.

Abstract: In the study, activated alumina was modified by calcium chloride, and after modification the phosphorus removal from aqueous solution increased by 13% or so. Then the activated alumina with and without treatment were subjected to characterization by the methods of the BET and SEM, and the adsorption characteristics of modified activated alumina were further studied at different contact time, pH values, adsorbent dosage levels and initial phosphorus concentration. Moreover, the equilibrium adsorption data for phosphorus were better fitted to Langmuir adsorption isotherm, and it means that the uptake of phosphorus preferably followed the monolayer adsorption process.