Abstract
In many countries, water pollution from industrial wastewater is a serious problem. This type of pollution can have a harmful impact on the environment, to reduce the effects of these pollutants, several physico-chemical methods are implemented, in particular adsorption on bioadsorbents, it is a common process to remove traces of pollutants from water, the aim of our work is to realize a comparative experimental study of isotherms and adsorption kinetics of methylene blue (MB) on three substrates: sugar cane bagasse (SCB), almond shell (AS) and walnut shell (WS). The results of equilibrium kinetics show that walnut shell (WS) binds better to methylene blue than other substrates. The results also show that the adsorption kinetics are described by the expression of the pseudo-second order model. The isotherms of adsorption of methylene blue (MB) by sugarcane bagasse (SCB), walnut shell (WS) and almond shell are perfectly described by Langmuir's model and that walnut shell adsorbs methylene blue better than other substrates.
Highlights
The wastewater from industrial discharges because of dyes from the industrial textile, cosmetics, printing, dyeing, food dyes and paper manufacturing[1], it present a danger for us and our environment because of their low biodegradability[2],in addition, some dyes degrade into compounds that have toxic, mutagenic or carcinogenic effects on living organisms [3].The world production of dyes is estimated by 800,000 t/year and the authors have classified the dyes in two categories according to their chemical constituents taking into consideration the nature of the chromophores that compose them: azo, anthraquinone, triarylmethane and phthalocyanine groups, others researchers have classified them according to the various application technologies: anionic or cationic[4]
To study the adsorption kinetics of the dyes at 25°C, a volume of 50ml of solution containing the dye of concentration 25mg/L is put in contact with an amount of 0.1g of adsorbent, at time t=0 in a 0.5L beaker, homogenization was carried out in an incubator type (Jisico-model J-NSIL_R) with a stirring speed equal to 127r/min, the sample is filtered in a Wothman type filtration system with a diameter of 0.45μm, the supernatant is immediately determined by a UV-Visible spectrophotometer type (Shimadzu 1601) at a wavelength of maximum absorbance of the WB
methylene blue (MB) adsorption kinetics on sugarcane bagasse, almond shell and walnut shell show the same patterns with a high MB adsorption capacity on the substrates during the first minutes
Summary
The wastewater from industrial discharges because of dyes from the industrial textile , cosmetics, printing, dyeing, food dyes and paper manufacturing[1] , it present a danger for us and our environment because of their low biodegradability[2] ,in addition, some dyes degrade into compounds that have toxic, mutagenic or carcinogenic effects on living organisms [3].The world production of dyes is estimated by 800,000 t/year and the authors have classified the dyes in two categories according to their chemical constituents taking into consideration the nature of the chromophores that compose them: azo, anthraquinone, triarylmethane and phthalocyanine groups, others researchers have classified them according to the various application technologies: anionic (acid, acid-mordant, direct, reactive, vat, sulfur dyes) or cationic (basic)[4]. Methylene blue is a cationic dye used for dyeing cotton, wood and silk is like a very toxic dye with harmful effects such as vomiting, increased heart rate, diarrhea, shock, cyanosis, jaundice, and quadriplegia[5] For this reason, it is necessary to treat wastewater containing methylene blue before discharge. For this reason several researchers have focused of certain adsorbents from naturel waste such as fruit trees, eggshells, palm waste or sawdust, for use Biosorbants with a view to replacing activated carbon[7] In this context, we proposed to test three substrates: sugarcane bagasse, almond shell and walnut shell, which are obtainable and realistic for developing countries and present a very important potential for wastewater treatment[8] .The aim of this work is a comparative study based on the adsorption kinetics and isotherms of the three selected substrates The Adsorption method is considered to be one of the most cost effective technologies, more precisely adsorption on activated carbon remains one of the most efficient treatment techniques, in the case of some dyes, overdosing of carbon is required for a better efficiency which makes the cost of the operation expensive. morver ,the regeneration of activated carbon is a delicate operation and there is no unanimity on its usefulness[6]. for this reason several researchers have focused of certain adsorbents from naturel waste such as fruit trees, eggshells, palm waste or sawdust, for use Biosorbants with a view to replacing activated carbon[7].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
