The aim of this study is the preparation of activated carbon using a suitable industrial sludge. Activated carbon produced by pyrolysis of paper mill sludge was chemically activated with various activating agents such as zinc chloride, potassium hydroxide and potassium chloride. A systematic investigation of the effect of impregnation ratio, activation temperature and activation time on the properties of activated carbon was done.
The activated carbon prepared from paper mill sludge in this study had maximum iodine of 764.80 mg/g with ZnCl2 as the activator. 2 Effect of concentration of activator on yield percentage and iodine value of activated carbon.
1.Introduction
Preparation of activated carbon
The chemical must generally be an acid, strong base, or a salt (phosphoric acid, potassium hydroxide, sodium hydroxide, zinc chloride, respectively). Chemical activation is preferred over physical activation due to the lower temperatures and shorter time required to activate material.
Objective of the project
4 The emphasis of this study is to optimize the processes involved in the production of activated carbons with the described surface properties (micro- or mesoporous structure) and specific end uses from paper mill sludge. The higher purity (when compared to biosolids), negative cost, high production rate, and strong carbon structure of paper mill sludge and rice husk make them both useful as precursors for carbon production. .
LITERATURE REVIEW
Literature review
- Classification
- Properties of activated carbon
Its economic disadvantage has stimulated the interest to use cheaper raw materials for the production of activated carbon.[12]. Recently, activated sludge has been produced as a result of wastewater treatment activities and has emerged as an interesting option for the production of activated carbon. 38]Adsorption of activated carbon is controlled by the chemical nature of the water phase, the solid phase and the.
Due to its antimicrobial/antiseptic properties, activated carbon with silver is used as an adsorbent for indoor water purification. In medical applications, activated carbon is used to treat poisonings and overdoses after oral ingestion.
PRECURSOR SELECTION
PRECURSOR SELECTION
- CHNS elemental analyser
The selection of the precursor (raw material) for the production of activated carbon was obviously the first step of the project. Typically, activated carbon is produced from carbon-containing source material such as wood, peat, coal and plant waste (e.g. walnut shells, fruit pits). Nowadays, one of the promising approaches for the production of cheap and efficient activated carbon is the reuse of waste sludge, such as biosolids produced in municipal or industrial wastewater treatment plants.
17 handling a wide variety of sample types, including solids, liquids, volatile and viscous samples, in the pharmaceutical, polymer, chemical, environmental, food and energy fields. If other elements such as chlorine are present, they will also be converted to combustion products such as hydrogen chloride. Various absorbents are used to remove these additional combustion products and some major elements, such as sulfur, if the determination of these additional elements is not required.
The combustion products are swept from the combustion chamber by inert carrier gas such as helium and passed over heated (about 600o C) high-purity copper. This copper may be located at the bottom of the combustion chamber or in a separate furnace. The function of this copper is to remove any oxygen not consumed in the initial combustion and convert any nitrogen oxides.
Detection of the gases can be performed in several ways, including (i) a GC separation followed by quantification using thermal conductivity detection (ii) a partial separation by GC ('frontal chromatography') followed by thermal conductivity detection (CHN but not S ) (iii) an array of separate infrared and thermal conductivity cells for detection of individual compounds. Quantification of the elements requires calibration for each element using highly pure 'microanalytical standard' compounds such as acetanilide and benzoic acid. Because many of these catalyst systems involve large amounts of precious metals such as platinum, palladium and rhenium, poor management of these tests would result in serious financial losses.
PREPARATION AND
CHARACTERIZATION OF ACTIVATED CARBON
- iodine value of the activated carbon
- Other physical prperties of activated carbon
- X-Ray Diffraction Measurements
- Fourier Transform Infrared Spectroscopy
- Scanning electron microscope analysis
Chemical activation of the sludge was then done using various activating agents such as ZnCl2, KOH and KCl. After completion of pyrolysis, the sample was removed from the reactor and crushed using a mortar and pestle. The difference between the original and final carbon weights represents the ash content per gram.
Moisture content was also obtained by weighing 10 grams of the carbon and placing it in an oven at 105 C for 3 hours. The difference between the initial and final mass of the carbon represents the water content of the sample. The wavelength of absorbed light is characteristic of the chemical bond, as can be seen in this annotated spectrum.
The signals are a result of interactions between the electron beam and atoms at or near the surface of the sample. Because the intensity of the BSE signal is strongly related to the atomic number (Z) of the sample, BSE images can provide information about the distribution of different elements in the sample. The size of the interaction volume depends on the landing energy of the electron, the atomic number of the sample and the density of the sample.
The beam current absorbed by the sample can also be detected and used to create images of the distribution of sample current. Unlike optical and transmission electron microscopes, image magnification in the SEM is not a function of the power of the objective lens. In an SEM, as in scanning probe microscopy, magnification is the result of the ratio of the dimensions of the raster on the sample to the raster on the display device.
RESULTS AND
DISCUSSIONS
Result and discussion
- Result of elememtal analysis and proximate analysis of the sludges
- Effect of time of impregnation on activated carbon products
- Effect of activation temperature on activated carbon products
- Effect of activation time on activated carbon products
- XRD analysis
- Scanning electron microscope analysis
But since the mass per unit volume of paper sludge is much higher than that of rice husk, it would be more economical to choose paper sludge as the precursor for the production of activated carbon. Therefore, paper sludge is fixed as our precursor in the further production and analysis of activated carbon. Moreover, the ZnCl2-activated product had the highest iodine value of 664.8 mg/g, indicating that its pore surface and structure were the best developed.
However, when the concentration of ZnCl2 was as high as 3N or more, the micropore structure of the activated carbon deteriorated due to excessive carbonization. 36 Figure 2: The influence of the concentration of the activating agent on the percentage of recovery and the iodine number of activated carbon. The effect of impregnation time on the iodine value of the activated carbon product is shown in Figure 3.
38 The activation temperature is a very influential parameter on the pore structure of activated carbon, which determines the adsorption capacity.[56] The variation of the iodine value in the activated carbon product was investigated as a function of the activation temperature. As shown in Figure 4, the iodine number gradually increased with the activation temperature and then decreased when the temperature exceeded 600 C. At a higher temperature (0.60 °C), the pore walls between adjacent pores were probably destroyed and the micropores were destroyed, which led to a decrease in the iodine number of activated carbon.
The changes in the iodine number of activated carbon produced from paper sludge versus activation time are shown in Figure 5. This band could also be attributed to the antisymmetric Si-OSi stretching mode resulting from the existing alumina-silica mineral in the sludge dioxide. samples [63]. The region 450-750 cm-1 shows two bands at 480 and 485 cm-1, which are related to the in-plane and out-of-plane deformation vibrations of the aromatic ring[64]. A sample of activated carbon produced from the best working conditions, such as 2.0 M ZnCl2 activation solution, impregnation time 20 h, activation temperature 600 C for 1 h, was analyzed in a scanning electron microscope.
The surface physical morphology of activated carbon was observed by a scanning electron microscopy (SEM) (S-2150, Hitachi High- Technologies Corp., Japan). SEM photo shows that a wide variety of pores are present in activated carbon along with fiber structure.
CONCLUSIONS
- Conclusions
The results of this study show that activated carbon with relatively high surface areas and pore volumes can be prepared from paper sludge by direct chemical activation. Activation with ZnCl2 produced activated carbons with better developed porosity than with KOH or KCl. The iodine number of the activated carbon product increased with the concentration of the ZnCl2 solution (up to 2 N).
As the impregnation time increased, the iodine content increased sharply, reaching a maximum value of 764.8 mg/g after 20 hours. The iodine value also increased with activation temperature up to 600 C, after which it gradually decreased, probably due to excessive carbonization. As the activation time was extended, the iodine value of ZnCl2-activated carbon increased and then reached its maximum after 1 hour.
A longer activation time could have a negative effect on the carbon structure and thus reduce the iodine value. To obtain a large carbon surface area and minimize the energetic costs of the process, the following is done. Under these conditions, activated carbon with a relatively high specific surface area of 737.6 m2/g and a high iodine number of 764.8 mg/g was produced from paper sludge by direct chemical activation.
The sludge-based activated carbon had an average pore diameter of 6.72 nm, and its total pore volume and micropore volume were 0.19 and 0.15 cm3/g, respectively, indicating its microporous and mesoporous character.
- References
Production and detailed characterization of bean husk-based carbon: efficient removal of cadmium (II) from aqueous solutions. Production of porous carbonaceous adsorbent from physical activation of sewage sludge: application to wastewater treatment. Microwave-induced drying, pyrolysis and gasification (MWDPG) of sewage sludge: vitrification of the solid residue.
Jeyaseelan S. and Lu G., Development of adsorbent/catalyst from activated carbon production from biological sludge by chemical activation with ZnCl2 and H2SO4. Sepulveda-Escribano, Effect of steam and carbon dioxide activation on micropore size distribution of activated carbon. Gonzalez, Use of steam and CO2 as activation agents in the preparation of activated carbon.
Procedure for the Preparation of Activated Carbon from Biosolids, Illinois Institute of Technology, Chicago, IL MS thesis (1998). Activated carbon developed from excess sewage sludge for the removal of dyes from dilute aqueous solutions. Production of granular activated carbon from walnut shell waste and its adsorption properties for Cu2þ ion.
