Synthesis and characterization of flax shive activated carbon

Abstract

Concern on dyes-laden effluent has intensified over the years. Dyes are toxic, stable to light hardly bio-degraded and cause irreparable harm to living organisms. Adsorption is widely recognized as an effective way to remove colorants from wastewater. Nevertheless, the search for improving the efficiency of adsorption is constantly being carried out with the help of new cheap activated carbon (AC). For adsorption studies, we used activated carbon obtained by pyrolysis of flax shive activated with K₂CO₃. Using X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, IR spectroscopy, low-temperature nitrogen adsorption, thermogravimetry, the characteristics of the AC were obtained. The effect of AC characteristics on the equilibrium adsorption capacity of methylene blue (MB) was studied. The maximum BET surface area of the AC equals 1246.1 and 1468.0 m²/g, which means its values are in the range typical of commercial activated carbons. The maximum equilibrium capacity of the obtained AC samples to adsorb the MB dye is 319.1 and 388.5 mg/g. The capacity for the activated carbons depended on the pyrolysis temperature, and cellulose content in flax shive and pore size distribution in carbon matrix. Converting lignocellulosic biomass into activated carbon could solve environmental problems such as agricultural waste and water pollutions control.

Keywords:

• Flax shive
• activated carbon
• methylene blue
• adsorption–desorption isotherm
• parameters
• morphology
• microscopy
• pyrolysis
• thermogravimetric analysis
• surface area
• electron microscopy