Adsorption is one of the most efficient physicochemical processes known to remove colour in textile industry effluents. Activated charcoal is conventionally the most used material for this purpose and although its efficiency is very high also is its price. The aim of this study was to know the variables that influence the adsorption process of wool reactive dye Yellow Lanasol 4G in a simulated textile effluent, on an inexpensive and abundant material, gallinaceous feathers, so as to optimize the operating conditions. Factorial experimentation within a certain domain was used to determine the influence level of several parameters, such as, temperature, initial pH of the solution, "size" and adsorbent's concentration and their interactions. A statistical analysis of the results showed that within the selected domain all the parameters have influence at a significance level of 1% excepting initial pH that only has influence at a significance level of 5%. Some of the possible interactions between these parameters also have significant influence on the adsorption process specially first order ones, including significance levels of 5 and 1%. In industrial practice it will be possible to take advantage of the prominent effect of a temperature increase on adsorption capacity as effluents of wool dyeing baths are already at an elevated temperature. Besides that as the influence of "granulometry" becomes rather smaller for higher temperatures there will be no need to grind the adsorbent. This means then that optimization of operating conditions in industrial wastewaters treatment using the studied adsorption technique will not imply additional costs except those concerning pH adjustment. This emphasizes the importance of gallinaceous feathers as an alternative to activated carbon.(undefined
