Activated Carbon Fabric (ACF) is widely recognized as versatile material having potential to act as a novel adsorbent, catalyst, as well as support to catalyst. developed by us indigenously in a continuous form under “Make in India” Concept.
We manufacture a cutting-edge technology technical textile activated carbon fabric in a continuous form. Our facility has the capability to manufacture the Activated Carbon Cloth with an in-house testing laboratory. Based on the end applications various functional elements such as copper, silver etc. are impregnated with the ACF to tailor the properties for removal of gas phase contaminants and pollutants. Activated Carbon Fabric (ACF) is widely recognized as versatile material having potential to act as a novel adsorbent, catalyst, as well as support to catalyst. Due to Multi-facet capability of ACF, it is used extensively in environmental application, air pollution emission control, medical and defence applications.
The strength of the ACF is improved by laminating with the non-woven base fabric. The lamination will be done using a hot gravure roller with a breathable adhesive. The lamination also improves the pleating of the cloth and therefore can be used for various industrial applications.
This is simple weaving pattern where the warp and weft yarns cross up and down alternatively. It is the simplest possible and most commonly used weave. It gives maximum number of interlacements in the fabric and therefore the fabric becomes very firm. As the yarns are having maximum possible interlacements, the crimp in the yarns is also higher as compared to other weaves.
Compound weave is characterised by diagonal line in the fabric which is created by the floats of the ends or picks. The simplest twill weave is two up one down (or one up two down) which repeats on three ends and three picks. In warp faced twill, the floats of ends predominate over that of picks. In contrast, the floats of picks predominate over that of ends in weft faced twill. In case of balanced twill, the floats of ends and picks are equal.
Satin and sateen weaves are characterised by Only one binding point in each end and pick within the repeat and no continuous twill line. The weave has a smooth appearance. Satin weave is warp faced whereas sateen weave weft faced. The fabrics have very smooth and lustrous appearance which is created by the long floats of either ends or picks.
In knitted weave yarn is looped around pin, the resultant fabric, a matrix of rows and columns of loops, is formed by creating a single element in each complete cycle of operation. Hence, if a fabric needs to have 100 loops in each row, then 100 cycles of operation would be needed to produce one row. Subsequently, loops of the row just completed would be transferred one after the other to another pin and in the process new elements are generated for the next row.
The strength of the ACF is improved by laminating with the non-woven base fabric / fabric of choice such as nylon, polyester. The lamination will be done using a hot gravure roller with a breathable adhesive. The lamination also improves the pleating of the cloth and therefore can be used for various industrial applications.
Activated carbons are fundamental adsorbents used in various fields extensively. Various modification methods have been developed to enhance the activity of activated carbon fabric towards the environmental pollution control applications. A number of transition metals including Cu, Fe, Co, Mn, Mo, V, Ce and Ni can be used as an effective catalyst in the treatment of gaseous pollutants. Metals such as copper and nickel impregnated activated carbon fabrics are synthesized and the CNFs/ACFs were prepared by growing CNFs on metal supported ACF using catalytic chemical vapour deposition (CVD) for removal of gaseous pollutants like SO2, NOx and VOCs.
The activated carbon fabric manufactured at Kristaa Clean Carbon Private Limited (KCC) is characterised for use in gas-phase contaminant removal in the filters. We have done research activities jointly with IIT Kanpur related to synthesis and characterization aspects of ACF. In addition, the ACF from KCC is impregnated with different metals and tests are performed to study the characteristics of the ACF when using against different gas pollutants as shown below.
i. The test results for removal of SO2 by dry adsorption and wet oxidation Further the effect of inlet SO2 concentration on the wet oxidation.
ii. Catalytic oxidation of NO into NO2 by raw and metal supported ACFs.
iii. Breakthrough profile study for adsorption of benzene over ACFs and further the ability to retain adsorption capacity after successive regeneration cycles.
iv. Evaluate the efficiency of ACFs for the adsorption of propionic acid. Spent ACFs was regenerated by water washing and its ability to adsorb propionic acid.
Flue gases from combustion of fossil fuels such as coal, petrol and diesel oil contain significant amount of sulphur dioxide which is a major atmospheric pollutant. ACF exhibits catalytic properties for the conversion of SO2 into sulphuric acid (H2SO4) making the overall removal process continuous without requiring regeneration. The test was performed for adsorption for Sulphur dioxide break through and the results demonstrates the SO2 adsorption of 18 mg/g of ACF manufactured by Kristaa Carbon.
The table below shows the catalytic oxidation of SO2 into sulphuric acid (H2SO4) by impregnated ACFs.
| Samples | Inlet SO2 concentration (ppmv) | Breakthrough time (minutes) | Steady state conversion time (minutes) | SO2 Conversion (%) |
|---|---|---|---|---|
| Compound weave with Impregnation | 2000 | 80 | 255 | 94 |
| Satin weave with Impregnation | 2000 | 110 | 270 | 93 |
| Compound weave with Impregnation | 4000 | 30 | 195 | 77 |
| X | 4000 | 30 | 220 | 75 |
Table 1:SO2 to H2SO4 Conversion using ACF
Nitrogen oxides (NOx) are the most toxic gases emitted into the atmosphere during the combustion of fossil fuels in industry and transport sectors. Nitrogen oxides (NOx) are severe harmful atmospheric pollutants for humanity and ecosystem. Nitrogen oxides (NOx) are the generic term for the group mainly consists of nitric oxide (NO), nitrogen dioxide (NO2) and nitrous oxide (N20). A number of common adsorbents, including activated carbons can be employed for the removal of NO2. However, the extent of physical adsorption of NO on activated carbons is generally low because NO is a supercritical fluid at the ambient temperature and the physical adsorption of supercritical fluids is limited due to the weak interactions between the adsorbent and adsorbate. One alternative to this process is the oxidation of NO into NO2. Selective catalytic oxidation (SC0) of NO in the flue gas at a low temperature is potentially an ideal technology.
As NO2 is easier to be removed by absorption than NO, especially, the maximum absorption efficiency could be achieved at the proper ratio of NO/NOx (NO/NOx = 50–60%).NO can be removed by catalytic oxidation at room temperature or relatively lower temperatures (50−350 °C) using different catalysts such as noble metals, or transition metals, supported on activated carbons. Activated carbon has been recognized as an effective catalyst for this reaction. Bimetallic oxides have also been used for the catalytic oxidation of NO. ACF or CNF-supported metal catalysts have also been used in the abatement of NO emissions by oxidation or reduction. Another advantage of catalytic oxidation is that the role of ACF of a catalyst, rather than an adsorbent, so that the ACF sites are continuously recovered following the desorption of NO2 from the surface. However, when considering real time application ACF should be cleaned at regular interval in order to maintain its quality and life time.
| Samples | NO2 Breakthrough time (minutes) | Steady state conversion time (Minutes) | NO-NO2 conversion (%) | |
|---|---|---|---|---|
| NO | NO2 | |||
| Compound weave | 50 | 290 | 400 | 30 |
| Satin weave | 90 | 370 | 420 | 30 |
| Compound weave with Impregnation | 10 | 300 | 360 | 26 |
| Satin weave with Impregnation | 30 | 160 | 270 | 32 |
| Satin weave with Imp (1st cycle) | 20 | 150 | 230 | 29 |
| Satin weave with Imp (2nd cycle) | 20 | 135 | 255 | 29 |
| Satin weave with imp (3rd cycle) | 20 | 140 | 240 | 29 |
Table 2:NO to NO2 Conversion using ACF
The Table 2 shows the conversion of the nitrous oxide into nitrogen dioxide using ACF.
The performance of the fabric after washing (Regeneration) was tested and there is no change or insignificant change in the conversion even though there is change in the steady state conversion time for NO and NO2.
Volatile organic compounds (VOCs) are primarily emitted by process industries dealing with the manufacture, storage, handling and distribution of paints, lubricants and liquid fuels etc. these organic compounds are classified as flammable, toxic, carcinogenic, and/or mutagenic agents, their presence in atmosphere even at low concentrations is of major environmental concern. The adsorption of gaseous VOCs onto porous adsorbents has been suggested as an innovative treatment process in the environmental application. Activated carbons are one of the best options due to their hydrophobic properties and their high surface area and because they are useful for adsorbing molecules with molecular weights between 45 and 130. Apart from adsorption capacity, the ability to retain adsorption capacity after successive adsorption and desorption is one of the major characteristics of the good adsorbent. Regeneration of activated carbon fabric is relatively easier than GAC and other adsorbents
| Samples | Breakthrough time (minutes) | Saturation Time (Minutes) | Adsorption capacity (mg/g) |
|---|---|---|---|
| Satin weave with Impregnation | 50 | 170 | 363 |
| Satin weave with Impregnation (1st cycle) | 50 | 135 | 256 |
| Satin weave with Impregnation (2nd cycle) | 55 | 130 | 232 |
| Satin weave with Impregnation (3nd cycle) | 40 | 120 | 247 |
| Satin weave with Impregnation (4nd cycle) | 40 | 100 | 223 |
Table 3: Test Results for Benzene Gas Adsorption
Carboxylic acids are used in various industries during the production of polymers, pharmaceuticals, solvents and food additives. Propionic acid is important member of carboxylic acid family which is used as intermediate during the production of other chemicals, a preservative for both animal feed and food for human consumption, especially polymers and artificial flavorings. In industry, propionic acid is produced by the hydro carboxylation of ethylene. A large amount of propionic acid is produced as a byproduct during acetic acid manufacturing. This propionic acid produced in human skin is major responsible for human body odor. Even though the amount of propionic acid produced in human body is low, intensity of smell is very high.
This section investigates the adsorption of propionic acid over activated carbon cloth. The influence of metal particles on breakthrough and adsorption capacity of propionic acid over ACFs also assessed. Further the study extended to evaluate regeneration ability of saturated ACFs by washing and air drying.
| Samples | Breakthrough time (minutes) | Saturation Time (Minutes) | Adsorption capacity (mg/g) |
|---|---|---|---|
| Compound weave | 70 | 155 | 120 |
| Satin weave | 90 | 210 | 160 |
| Satin weave with CU | 50 | 150 | 83 |
| Satin weave with Ni | 40 | 135 | 84 |
Table 4 :Test Results for Propionic Gas ,mm
Table 3 summarizes the findings of propionic acid adsorption experiments and the amount of propionic acid adsorbed was almost in linear relationship with surface area and pore volume.
| Samples | Breakthrough time (minutes) | Saturation Time (Minutes) | Adsorption capacity (mg/g) |
|---|---|---|---|
| Satin weave | 70 | 190 | 126 |
| Satin weave (1st cycle) | 60 | 150 | 100 |
| Satin weave (2nd cycle) | 40 | 120 | 62 |
| Satin weave (3nd cycle) | 30 | 105 | 54 |
| Satin weave (4nd cycle) | 30 | 105 | 56 |
Table 5: Test results of regenerated ACF
It can be observed from Table 5 there is no significant change was observed in subsequent adsorption regeneration cycles.
| Description | KSorb 250 | KSorb 200 | KSorb 175 | KSorb 150 |
|---|---|---|---|---|
| Fabric Structure | Satin Weave | Comp Weave | Plain Weave | Knitted Weave |
| Weight in GSM* | 250 | 200 | 175 | 150 |
| Iodine Number* | >900 | >900 | >800 | >700 |
| CTC* | >55 | >55 | >45 | >40 |
* Indicative characteristics of the product. Contact us for more detailed information.
Kristaa Clean Carbon Private Limited,
9,Sribalasubramaniam Nagar, Peelamedu,
Coimbatore 641004, Tamil Nadu, India.
CIN: U74999TZ2014PTC020208
Phone: +91 422 2574279 / +91 9740777645,
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