Magnetite nanoparticles impregnated pyrolysed coconut coir for water softening applications

Abstract

Development of novel advanced materials for water softening applications is a timely need. Water softening efficiency of activated and pyrolyzed coconut coir (PCC) was found to be higher than that of activated carbon derived from coconut shell charcoal. For further enhancing the water softening capacity of PCC, magnetite nanoparticles impregnated pyrolyzed coconut coir (M-PCC) was synthesized by an in-situ one-pot synthesis method. In this approach, the raw coconut coir was dipped in a solution of 1.00 mol dm-3 FeCl3, 1.00 mol dm-3 FeSO4.7H2O and 5.00 mol dm-3 NaOH followed by pyrolysis at 450℃ under N2 gas flow and evaluated its efficiency in water softening applications. The process parameters, including contact time, adsorbent dose and pH, were optimized using a representative natural water sample (total hardness - 370 mol L-1). Characterization studies confirmed the successful impregnation of magnetite nanoparticles into pyrolyzed coconut coir. Powder X-ray diffraction and Fourier transform infrared spectroscopy confirmed the formation of magnetite phase and provided information on interactions with the carbon matrix. M-PCC thus prepared was capable of removing total hardness of natural hard water over 80% with an adsorbent dose of 0.6 g/50 mL at a water pH of 6–8 by double filtration. Therefore, it can be claimed that magnetite nanoparticles impregnated pyrolyzed coconut coir is suitable as an adept adsorption material in developing next-generation methodologies for restoring water softness.

Keywords

• coconut coir, magnetite nanoparticles, pyrolyzed coconut coir, water hardness