Valorizing waste crab shells as renewable biomass fillers in polyaniline for ammonia gas detection

Abstract

Seafood waste possesses an interesting physicochemical characteristic that can be used to produce lucrative end products. In the present study, an attempt was made to valorize waste crab shells as renewable biomass fillers in the synthesis of polyaniline/crab shell (PANI/CS) composites. PANI was synthesized via chemical oxidative method and the waste CSs were added ex-situ into the as-synthesized emulsion of PANI. The physicochemical properties of PANI/CS composites were evaluated by Fourier transform infrared (FTIR), ultraviolet–visible (UV–Vis), X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques. Sensor responses of PANI/CS composites in different concentrations of NH3 gases were reported by using a multimeter with the aid of home-made gas chamber. PANI/CS 20% outperformed among all the prepared PANI/CS composites with a correlation coefficient of R2 = 0.9886. Hence, PANI/CS 20% was selected to undergo sensor performance studies such as selectivity, reusability, and long-term stability. PANI/CS 20% exhibited good selectivity towards NH3 gas in the presence of others interfering species such as hexane, acetone, diethyl ether and hydrochloric acid fumes and showed stability up to 1 week with 5 cycles of reusability. In conclusion, the study proved that waste biomass of CSs can be effectively incorporated into the PANI matrix and applied as an NH3 gas sensor with an excellent limit of detection of 9.8 ppm.