Description:[0003] Carbon is the most abundant, naturally occurring substance on earth. It may be found in a wide range of molecular and structural forms, including graphite, diamond, fullerene, amorphous carbon, porous carbon, and others, all of which have numerous uses. These forms have uses in super capacitors, batteries, catalysis, and other industries because of their high surface area, great mechanical strength, electrical, thermal, and optical qualities.
[0004] Agricultural and forestry activities generate a substantial amount of waste from harvestable output. The production of 140 Gt of biomass waste annually offers challenging management issues. Crop stalks, leaves, roots, fruit peels, and seed/shell wastes make up the majority of agricultural biomass wastes and are normally thrown away or burned but could be an important source of feedstock material. Depending on the source of the biomass waste, the majority of this sort of waste contains a significant amount of carbon. The production of carbon from bio waste materials can be a clean alternative for fossil fuels, which accounts for ~76% of the total greenhouse gas emissions.
[0005] Researchers from all across the world have used a variety of naturally occurring biomass materials for the synthesis of valuable functional carbon materials. Among the different biomass materials coconut palm is considered as the significant source of carbon production because it is the most common agriculture all around the world. For the production of 1 tons of carbon, 50000 coconuts are used. Thus from the above data, it is observed that 5% of the global demand for carbon can be met from coconut shell itself. This confirmed the importance of coconut as a suitable precursor for carbon production. In one of the research, graphitic-type activated carbon from coconut shell (DOI: 10.1039/d0ra09182k) has been reported to show high degree of crystallinity, suitable morphology and specific surface area ranging from 586 m2 g-1 to 1998 m2 g-1. Patent application, CN114455950A, discloses a method for preparing a graphite boat from lignin-rich plant bodies such as bamboo, pine, corn stover, coconut shell or tea seed oil shell using pyrolysis and volatilization. Another research “Characteristics of Activated Charcoal from Coconut Midribs in Jumputan Waste Adsorption Process”, describes activated carbon production from coconut midrib in three stages namely preparation, carbonization and activation (https://www.researchgate.net/ publication/338965583 ).
[0006] However, fabrication of the carbon materials with above-mentioned processes involves use of strong acids, high temperatures and cannot be performed without complex machineries. Furthermore, coconut rachis has not been readily used in preparing graphite or activated carbon for COD and BOD reduction in liquid waste or in gas filtration. Hence, there has long been a need in the art for preparation of carbon precursors from coconut waste that is easy to fabricate, cost-effective and is suitable for energy storage application. In this regard, the method and products according to the present invention substantially departs from the conventional concepts and designs of the prior art.
[0007] These and other advantages will be more readily understood by referring to the following detailed description disclosed hereinafter with reference to the accompanying drawing and which are generally applicable to other solar thermal evaporators to fulfill particular application illustrated hereinafter.
, Claims:1. A method (100) of preparing activated carbon (200) with high surface area and narrow pore size distribution from coconut rachis, the method comprising the steps of:
a) providing sun dried coconut rachis (101), wherein the coconut rachis is sun dried for 48 hours;
b) powdering the sun dried coconut rachis (102) followed by oven drying (103) at 110°C for 48 hours;
c) pre-carbonizing (104) the oven dried powder at a temperature ranging from 240-280°C for 2 hrs;
d) pulverizing (105) the pre-carbonized oven dried powder using a mortar and pestle;
e) carbonizing (106) the pulverized powder in a muffle furnace under nitrogen flow at a temperature ranging from 400-500°C for 2 hrs to form a crystalline carbon;
f) mixing the carbonized carbon with a strong base solution (107) to form a colloid;
g) drying the colloid at 100°C followed by annealing at 450- 500°C for 4 hours under nitrogen flow (108) to obtain a powder;
h) washing (109) the powder with distilled water to obtain activated carbon; and
j) oven drying (110) the activated carbon (300).

2. The method as claimed in claim 1, wherein in step f) the carbonized carbon is mixed with 6M KOH solution in 1:4 weight ratio.

3. The method as claimed in claim 1, wherein the method provides a pore size distribution of 2.09 nm or less.

4. The method as claimed in claim 1, wherein the obtained activated carbon (200) is characterized by a BET surface area of 1600 m2 g-1 or more and a pore size of 2.09 nm or less.

5. The method as claimed in claim 1, wherein the obtained activated carbon (300) gives an XRD pattern with peaks at 2? = 26º and ~44º corresponding to (002) and (100) planes to confirm amorphous structure of carbon

6. The method as claimed in claim 1, wherein the obtained activated carbon (200) comprises a pore volume of 0.855 cm³/g or a void diameter of 6 µm or less.