They were characterized by evaluating surface area, iodine number, pore size distribution, and concentration of surface functional groups. The chemically activated carbon largely featured micropore struc- ture, while the physically activated carbon mainly featured macropore structure. The concentration of surface functional groups was determined by Boehm titration method, which suggested that dif- ferent types of surface functional groups are randomly distributed on chemical activated carbons, while it is limited for physical activated carbon. The microporosity along with surface functional groups provided a unique property to chemically activated carbon to adsorb Methylene Blue dye to a large extent.
Get Full Essay Get access to this section to get all help you need with your essay and educational issues. Microporosity and Surface Functionality of Activated Carbon Essay Sample Abstract Activated carbons have been prepared from jute stick by both chemical and physical activation methods using ZnCl2 and steam, respectively.
The activated carbons were characterized by evaluating surface area, iodine number, pore size distribution, surface functional groups and surface textural properties. Based on the analysis, the activated carbon prepared by chemical activation method, ACC featured micropore structure, while the activated carbon prepared by physical activation, ACS largely featured macropore structure.
The microporosity along with surface functional groups provided a unique property to ACC to adsorb methylene blue dye, which is a representative basic dye for textile industries, in a large extent compared to ACS. The adsorption of dye using both ACC and ACS was also affected by the adsorption parameters such as adsorption time, temperature and pH.
Comparatively higher temperature and pH facilitated dye adsorption significantly, especially for ACC.
Activated carbon, Jute stick, Chemical activation, Methylene blue, Adsorption 1. Introduction Activated carbons AC possess high surface area with porous structures and are widely known as efficient adsorbents for both gas and liquid phase adsorptions.
The increasing environmental concern significantly increased the applicability of AC for industrial pollutants separation. The effluents from industries, such as textile, leather, paper, ink and cosmetics as well as from the industries that produce dyes are severely contaminated with dyes, pigments, surfactants and many other toxic chemicals.
These contaminated effluents ultimately go to the surface water reservoir. The dye contaminated water even in a very low concentration is visible and aesthetically unacceptable. As most dyes are toxic and primarily contaminate surface water, the water biota is the primary victim of dye contamination, and long exposure of dyes in water often causes food chain contamination, resulting in adverse health effect.
Hence, it is mandatory to reduce contaminant concentration in effluent bellow acceptable range before being released into the environment by utilizing proper treatment process.
Due to the technological advancement, numerous processes have been attempted to remove dyes and other contaminants from effluent in the last few decades.
The most frequently used processes are adsorption , oxidation—ozonation , photocatalysis , biological treatment , coagulation—flocculation  and membrane separation . Among the processes, the adsorption is the most versatile and economic due to many advantages.
Although the biological treatment for organic compounds removal from water is some extent effective, the removal of organic refractory contaminants has proven to be very ineffective.
Even the contaminants are non reactive, the adsorbent can remove contaminants satisfactorily . A number of adsorbents are used for dye removal including agricultural wastes, wood materials, industrial wastes and synthetic materials . Activated carbons, which can be produced from agricultural wastes, are known as very effective adsorbents for dye adsorption .
These properties of AC can be regulated by regulating the preparation methods and their conditions as well as by selecting the precursor materials.
A very selective AC can be prepared with a precise preparation method from a suitable precursor for a specific dye separation. The adsorption of dye molecules onto the AC surface depends on the pore size distribution, surface functionality as well as the size and shape selectivity of the molecules to be adsorbed.
For an optimum adsorption, the molecular size of the adsorbates needs to be quite fitted to the pore size of the AC. Both in the gas phase and liquid phase separations, the micro- and mesopores play major role [17, 18].
The macropore structure leads to the smaller surface area of AC as well as the multilayer adsorption is limited in macropore, which attributes to the lower adsorption capacity.
Therefore, the pore size and structure of AC need to be optimized for a specific separation. The activated carbon from hard wood is especially used for gas separation and that is from soft wood is used for solution phase separation. However, the physical activation using steam often produces activated carbon with macropore structure .
Activated carbons from the soft cellulosic precursors, especially from agricultural residues are widely used for dye molecule separation from solution . Phenol and many inorganic contaminants such as arsenic and mercury are also potentially environmental hazards and are separated using AC prepared from agricultural residues .
The presence of functional groups on AC surface provides polarity, which in turns influence adsorption properties. The IR spectroscopic studies represented that during heat treatment at high temperature to produce AC, most of the reactive functional groups on the surface of biomass are released as H2O, CO2 and many other small molecules, leaving behind quinolic, etheric, phenolic and ketonic functional groups .
These oxygen containing surface functional groups provide acidic as well as basic properties depending on the ring structures . The extent of ring condensation during activation has also a role to play to form a wide basal surface of AC, which facilitates the accommodation of dye molecules in adsorption.The adsorption capacities of the solutes were correlated with the microporosity properties of the activated carbons including micropore volume and external surface area.
Finally, the adsorption characteristics of the present carbons was compared with those . Role of microporosity and surface functionality of activated carbon in methylene blue dye removal from water. / Asadullah, Mohammad; Kabir, Mohammad Shajahan; Ahmed, Mohammad Boshir; Razak, Nadiah Abdul; Rasid, Nurul Suhada Abdur; Aezzira, Airin.
characteristics of adsorbent (surface area, pore size distribution (PSD), and surface chemistry) and adsorbate (molecular weight, size, functional groups present, polarity, hydrophobicity, solubility), and the background solution conditions (pH, temperature, presence of competitive solutes, ionic strength) .
isotherm for water on a typical activated carbon, without oxygen surface complexes, is type III, showing very low interaction between the molecules of water and the carbon surface.
The microporosity along with surface functional groups provided a unique property to chemically activated carbon to adsorb Methylene Blue dye to a large extent. The microporosity along with surface functional groups provided a unique property to chemically activated carbon to adsorb Methylene Blue dye to a large extent.
The adsorption of dye was also affected by the adsorption parameters such as adsorption time, temperature and pH.