Experimental data of CaTiO3 photocatalyst for degradation of organic pollutants (Brilliant green dye) – Green synthesis, characterization and kinetic study

The data presented here focuses on the physicochemical characterization of perovskite CaTiO3 nanoparticles (orthorhombic) as photocatalyts and the kinetic study of their photodegradation performance toward organic pollutant, i.e. brilliant green (BG) which is azo derivatives dye. The CaTiO3 nanoparticles was synthesized using chicken eggshell-derived CaCO3 and anatase TiO2 with molar ratio of (1:1), (1:3), (2:5), and (2:7). The physical and microstructural properties of CaTiO3 were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), Fourier Transform Infrared (FTIR) and UV/vis spectrometer. The effect of initial dye concentration, catalyst composition, and catalyst dosage on the adsorption mechanism of dye on CaTiO3 was investigated in jacketed photoreactor under UV irradiation. The analysis reveals that BG molecules are efficiently chemisorbed, as indicated by pseudo first order kinetic, and degraded within 120 min. Considering the low-cost preparation process and high photocatalytic performance, the resultant CaTiO3 can further be used as an efficient photocatalyst for organic pollutant removal from aqueous and industrial wastewater.


a b s t r a c t
The data presented here focuses on the physicochemical characterization of perovskite CaTiO 3 nanoparticles (orthorhombic) as photocatalyts and the kinetic study of their photodegradation performance toward organic pollutant, i.e. brilliant green (BG) which is azo derivatives dye. The CaTiO 3 nanoparticles was synthesized using chicken eggshell-derived CaCO 3 and anatase TiO 2 with molar ratio of (1:1), (1:3), (2:5), and (2:7). The physical and microstructural properties of CaTiO 3 were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), Fourier Transform Infrared (FTIR) and UV/vis spectrometer. The effect of initial dye concentration, catalyst composition, and catalyst dosage on the adsorption mechanism of dye on CaTiO 3 was investigated in jacketed photoreactor under UV irradiation. The analysis reveals that BG molecules are efficiently chemisorbed, as indicated by pseudo first order kinetic, and degraded within 120 min. Considering the low-cost preparation process and high photocatalytic performance, the resul-tant CaTiO 3 can further be used as an efficient photocatalyst for organic pollutant removal from aqueous and industrial wastewater.
© 2020 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license.
( http://creativecommons.org/licenses/by/4.0/ ) Table   Subject Materials Chemistry Specific subject area Photocatalysis Type of data Table, Image, Graph How data were acquired CaTiO 3 powder was prepared using wet chemical synthesis, in which chicken eggshells as precursor source were collected from the farm field in Samboja, Balikpapan, Indonesia. Physicochemical characterizations were carried out by scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier Transform Infrared (FTIR) spectrometer. The kinetic data was fitted using both pseudo first order and pseudo second order adsorption model.

Data format
Raw and Analyzed Parameters for data collection X-ray diffractometer was operated at 40 kV, and 40 mA with Cu-K α as a radiation source. Diffraction patterns were scanned between 10 and 100 °(2 θ) with resolutions of 0.05 °FTIR spectra were collected in wavenumber range between 400 and 4000 cm −1 . SEM images were collected at 100 kV accelerating voltage with 500 × magnification. UV photoreactor was filled with 10 ppm of brilliant green solution and run under continuous stirring (500 rpm) at 28 °C.

Description of data collection
Morphology of CaTiO 3 was assessed using SEM (FEI Inspect 21). XRD patterns were collected using a diffractometer (PAN analytical type X'Pert Pro). FTIR spectra were recorded using Thermo Nicole is50 spectrometer at room temperature. Degradation of aqueous brilliant green (BG) dyes was probed under UV photoreactor using simulated UV irradiation (T5-UV7W, 254 nm). UV/vis absorption spectra to probe degradation of brilliant green dye were measured using UV/vis spectrometer (Rayleigh UV-9200).

Value of the Data
The CaTiO 3 nanomaterial investigated here renders perovskite based photocatalyst which has been proven its functionality for photocatalytic degradation of azo dyes derivative, i.e. brilliant green (BG). The current data, particularly the kinetic of degradation of aqueous BG solution, is useful for relevant studies of photocatalytic azo dye degradation using other catalysts, which is not limited to pristine CaTiO 3 , CaCO 3 , TiO 2 or composite materials. The photocatalytic degradation data suggest that the current prepared CaTiO 3 materials can be readily utilized as photocatalyst for wastewater treatment in textile industry, food processing industry, and for water treatment in water utility company. The physicochemical data highlights the current synthesis route could not yield 100% CaTiO 3 and hence, optimization of precursor composition and mechanochemical as well as post heat treatment will be the focus of further research. Table 1 Reaction rate constants (K) derived from both pseudo first order (K 1 ) and pseudo second order (K 2 ) as well as the corresponding coefficient of determination (R 2 ) obtained for photodegradation of BG using different CaTiO 3 com position. The preparation of CaTiO 3 nanomaterial investigated here is considered low cost and green since the wet chemical synthetic route didn't require sophisticated apparatus while the precursor employed chicken eggshells (waste or by-product of farming activities).
Having characterized the physicochemical properties, the photocatalytic degradation of aqueous BG dyes using the resulting CaTiO 3 catalyst were investigated by probing the temporal change of UV/vis absorption spectra ( Fig. 4 , representative/selected raw data is available in the Supplementary Material). Kinetic of degradation mechanism to understand the adsorption process of dye molecules toward catalyst surface is evaluated using both pseudo first order and pseudo second order kinetic fit ( Figs. 5-7 ). For pseudo first order fit, a plot of ln(C o /C t ) vs t (C 0 and C t denote concentration at initial condition and time t, respectively) results in a linear curve, in which the slope equals to the observed rate constant (K 1 ) [6] . Meanwhile, pseudo second order fit, the off-set of the linear plot of t/q e vs t, where q e is the concentration at equilibrium condition, yield the rate constant (K 2 ) [6] . The rate constant of photocatalytic degradation upon varying the catalyst composition, catalyts dosage and pollutant concentration is summarized in Tables 1-3 . The analysis indicates that increasing the fraction of TiO 2 in the precursor composition, i.e. CaCO 3 /TiO 2 molar ratio, alters the adsorption behavior from physisorption (following second order reaction, R 2 > 0.9) to chemisorption (following first order reaction, R 2 > 0.9). In addition, increasing amount of CaTiO 3 catalysts implies on the increasing chemisorbed BG molecules and faster catalytic reaction. Even though the degradation rate is slower than the highest reported in literature using CaTiO 3 [7][8][9] , the photodegradation rate of BG molecules using CaTiO 3 in this work (0.0185 ppm • min −1 ) is found comparable to the photodegradation rate

Table 2
Reaction rate constants (K) derived from both pseudo first order (K 1 ) and pseudo second order (K 2 ) as well as the corresponding coefficient of determination (R 2 ) obtained for photodegradation of BG using different amount of CaTiO 3 (2:7).  Table 3 Reaction rate constants (K) derived from both pseudo first order (K 1 ) and pseudo second order (K 2 ) as well as the corresponding coefficient of determination (R 2 ) obtained for photodegradation of various BG concentration using 50 mg of CaTiO 3 (2:7).

Experimental design, materials, and methods
Synthesis of CaTiO 3 nanoparticles employed a precursor mixture of commercial anatase TiO 2 (MTI, 99%) and CaCO 3 extracted from eggshells [9] . The collected chicken eggshells were washed thoroughly with ethanol-water mixture and dried at ambient atmosphere for 48 h. Afterwards, the dried eggshells were grounded for 30 min into fine particles. The fine powder was treated with 0.1 M HCl for 1 h and then washed with distilled water prior heat treatment at 100 °C for 3 h. The heat-treated samples were then sieved (300 mesh) to yield fined CaCO 3 nanoparticles (up to 86.6%). The initial step for CaTiO 3 synthesis was to prepare a mixture of CaCO 3 and TiO 2 in different CaCO 3 /TiO 2 molar ratio of (1:1), (1:3), (2:5), and (2:7), which was dissolved in 100 ml of ethanol and homogenized by continuous stirring at 300 rpm for 2 h at room temperature. The suspension was filtered and washed with distilled water several times and dried in an oven at 100 °C for 2 h. The dried white powder was subsequently grounded into fine and homogeneous granules, and eventually annealed at 900 °C for 4 h. Characterization of CaTiO 3 nanoparticles follows the description in the specifications table (vide supra ) .
Initial investigation of 10 ppm brilliant green (BG) photodegradation was carried out employing different CaTiO 3 com position, i.e. different CaCO 3 /TiO 2 molar ratio, in a custom-made photoreactor under UV irradiation [10,11] . Additionally, the dosage of CaTiO 3 and the initial concentration of BG solution were varied. It should be noted that the reactor was isolated from ambient light so that the photodegradation was driven only by UV irradiation. The solution in photoreactor was also continuously stirred to increase contact between CaTiO 3 photocatalyst and BG molecules and hence, driving a rapid photodegradation. Photodegradation of BG was monitored through the absorption change (300 nm < λ < 800 nm) measured using UV/vis spectrometer.
The decrease of BG optical density was used to determine the decreasing BG concentration due to the catalytic activity of CaTiO 3 , which was later used to evaluate the adsorption kinetics.