Synthesis and Characterization of Calcium Oxide (CaO) Nanoparticles and Their Application in Adsorption of Indigo Carmine Brigitta Stacia Maharani (a), Fitri Khoerunnisa (a*), Mita Nurhayati (b), Hendrawan Hendrawan (a), Eli Hendrik Sanjaya (c), Wijayanti Dwi Astuti (d)
(a) Universitas Pendidikan Indonesia, Bandung 40154, Indonesia
(b) Department of Advanced Science and Technology Convergence, Kyungpook National University, 2559 Gyeongsang-daero, Sangju-si 37224, South Korea
(c) Department of Chemistry, Universitas Negeri Malang, Malang, 90222, Indonesia
(d) Department of Electrical Engineering dan Informatics, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
Abstract
This study aims to determine the optimum conditions for the synthesis of CaO nanoparticles through the co-precipitation method, to determine the characteristics of the CaO nanoparticles synthesized by the co-precipitation method and to investigate the effect of the performance of CaO nanoparticles on the effectiveness of CaO nanoparticles as an adsorbent for indigo carmine waste. The CaO nanoparticle synthesis method used in this study is the co-precipitation method, while the adsorption application uses the batch method. CaO nanoparticles were analyzed using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Fourier-transform infrared spectroscopy (FTIR) while the adsorption test was analyzed using an Ultraviolet-Visible (UV-Vis) spectrophotometer. CaO nanoparticles have optimum conditions with a NaOH concentration of 1M with the highest yield percentage up to 74.56% and a formation temperature of 600-degree Celcius. The successful formation of CaO nanoparticles was shown by the 2-theta diffraction peak of 23.12- 32.4- 39.6 and 51.02 which are identical to CaO with an hkl lattice structure of (200), (220), (311), and (331) respectively and the crystal size reaches 4.96 nm. SEM images also support the formation of CaO nanoparticles which reach a size of 50 nm and their uniform distribution. IR spectra show that CaO nanoparticles already have Ca-O bonds at wavelengths of 3640 and 791 cm-1 and Ca-O stretching vibrations at 1400 and 860 cm-1. Adsorption study of indigo carmine with CaO nanoparticles used an adsorbent dose of 10 mg, an adsorbate concentration of 100 ppm and a contact time of 50 minutes. In modeling the most suitable adsorption isotherm is the Koble-Corrigan model with a R square of 0.99 and a chi square value of 0.39. Whereas in the adsorption kinetics modeling, the pseudo 2nd order model is the most suitable model R square value of 0.99 and the Qmax value (experiment) is close to the Qe value (calculation).
