Abstract:
Poultry litter is one type of agricultural waste being generated in our country as a result of raising
more than 146 million commercial and domestic poultry birds. This waste find its final disposal in
the field as soil fertilizer or amendment. However, the uncontrolled use of poultry litter for this
purpose can result in environmental impacts such as the emission of methane, a greenhouse gas.
Various other options like thermochemical conversion of this waste can be a solution to this
problem. Poultry litter can be a low-cost carbon sources for synthesis of Carbon Nanotubes
(CNTs). In this study efforts have been mad to utilize the cheap and readily available carbon source
for synthesis of CNTs in the presence of Ni/Mo/MgO as a catalyst through combustion technique.
Molar ratios of Ni, Mo and MgO as catalytic precursors were optimized using response surface
methodology (RSM) to obtain the maximum CNTs yield. The optimum mole ratio of catalyst
(4:0.2:1) was found to yield more carbon product. Further, process parameters such as combustion
temperature, time, and polymer & catalyst weight were also optimized by RSM using Box–
Behnken three-level and four-factorial design. The best possible combination of process
parameters noted were (combustion time of 12 min, at a temperature of 825oC, and catalyst weight
of 100 mg) in order to gain yield of CNTs (44.21%). Structure and morphology was confirmed
through X-ray Diffractometer (X-RD) & Scanning Electron Microscopy (SEM). The
environmental application of these carbon nanotubes was tested in lab with synthetic chromium
solution. Different experimental conditions (pH, dosage of adsorbent and the contact time) that
enhances the adsorption of Cr (VI) by carbon nanotubes were studied. UV-Visible
spectrophotometer was used to measure the absorbance of Cr (VI) at 540 nm. It was found that
81.83% of Cr (VI) removal is achieved by using 8 mg of CNTs at pH 3 with 400 rpm, and 180 min
of contact time. This makes CNTs from poultry waste as potential adsorbent for heavy metals.
