Data for efficiency comparison of raw pumice and manganese-modified pumice for removal phenol from aqueous environments—Application of response surface methodology

Present deadest collection was aimed to evaluate the efficiency of raw pumice (RWP) and Mn-modified pumice (MMP). Response surface methodology (RSM) based on the central composite designs (CCD) was applied to evaluate the effects of independent variables including pH, adsorbents dosage, contact time and adsorbate concentration on the response function and the best response values were predicted. The Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the adsorbents. Based on acquired data, the maximum efficiency removal of phenol was obtained 89.14% and 100% for raw and Mn-modified pumice respectively. The obtained data showed pH was effective parameter on phenol removal among the different variables. Evaluation of data using isotherms and kinetics models showed the fitted with Langmuir isotherm and pseudo second order kinetic for both adsorbents. According to obtained data was observed that modification of pumice can improve the efficiency removal of phenol to meet the effluent standards.


a b s t r a c t
Present deadest collection was aimed to evaluate the efficiency of raw pumice (RWP) and Mn-modified pumice (MMP). Response surface methodology (RSM) based on the central composite designs (CCD) was applied to evaluate the effects of independent variables including pH, adsorbents dosage, contact time and adsorbate concentration on the response function and the best response values were predicted. The Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the adsorbents. Based on acquired data, the maximum efficiency removal of phenol was obtained 89.14% and 100% for raw and Mn-modified pumice respectively. The obtained data showed pH was effective parameter on phenol removal among the different variables. Evaluation of data using isotherms and kinetics  [2].

Value of the data
The obtained data of this dataset showed that Mn-modification effect on adsorbent led to increasing of equilibrium sorption capacity for removal of phenol.
Due to cheap and high availability of this type of adsorbent in Iran, the efficiency of it can be improved by making these simple modifications and so the application of it in water and wastewater treatment will be increased.
The obtained data of present dataset can be used for design and development of future similar studies. Because in this study, the optimal conditions for the removal of phenol by FSP are determined. Therefore, the range of future study variables can be determined based on the optimal conditions of this dataset.
The raw data of this dataset was analyzed using the RSM method [3][4][5][6]. Therefore, the data related to the optimization conditions and the determination of the effect of each parameter will be very understandable for other researchers.
1. Data Table 1 shows the experimental conditions and results of central composite design. The obtained data indicated the maximum efficiency removal of phenol was obtained 89.14% and 100% for RWP and MMP respectively. Tables 2 and 3 revealed the estimated regression coefficients and ANOVA dataset from the central composite design experiments for RWP and MMP respectively. Table 4 indicated Analysis of variance (ANOVA) for fit of Phenol removal efficiency by RWP and MMP. Table 5 shows the parameters of Langmuir and Freundlich isotherms for phenol adsorption on RWP and MMP. The acquired data indicated the data were obeyed the Langmuir isotherm for RWP (R 2 ¼0.9798) and MMP (R 2 ¼0.9944). Also, Table 6 indicates kinetic model parameters. The revealed data were obey the pseudo second order for RWP (R 2 ¼0.9748) and MMP (R 2 ¼ 0.9971). Fig. 1 illustrates the Fourier transform infrared spectroscopy (FTIR) and XRD patterns of RWP and MMP. Fig. 2 demonstrates the SEM images of RWP and MMP. Fig. 3 shows trend of phenol removal efficiency by RWP. Fig. 4 shows the response surface plots for phenol removal efficiency by RWP. Fig. 5 indicated the normal probability plot of residual related to phenol removal efficiency by RWP. Fig. 6 shows the response surface plots for phenol removal efficiency by MMP. Fig. 7 indicated the normal probability plot of residual related to phenol removal efficiency by MMP.

Pumice preparation and its modification using manganese
Early preparations of raw scoria powder (RSP) were performed according to Moradi et al. study [2]. The coating of particles with manganese (Mn) was carried out as follows: 150 mL of 0.01 M Mn (NO 3 ) 2 solution and certain amount of raw pumice powder were transferred to a beaker. Then, pH was adjusted via HCl and NaOH 0.5 M. The beaker was putted on shaker at ambient temperature (25°C 7 1°C) for 72 h and dried at 105°C for 24 h. the uncoated Mn was removed several times by distilled water and dried in 105°C for 24 h [7].

Characteristics of RWP and MMP
The Fourier transform infrared spectroscopy (FTIR) analysis was conducted by WQF-510 Model. The chemical characteristics and surface morphology were determined by an XRD (Shimadzu XRD-6000) and scanning electron microscope (SEM; Philips XL30) respectively were used to Characteristics of RWP and MMP [8][9][10][11].

Experimental design using RSM
Because the existence of many parameters which affected the results of experiments, achieve to the optimal conditions of experiments is an important strategy for determining the effective parameters and reducing the costs. Hence, attention to mathematical methods was developed to evaluate the obtained data. RSM based on central composite design (CCD) is a proper method to determine the best conditions of experiments for minimization of number of experiments and to survey of the relationship between the measured responses (phenol removal) and number of independent variables with the goal of optimizing the response [12][13][14][15][16]. (Design Expert 8.0, Stat-Ease Inc., Minneapolis, MN, USA) Table 7 illustrated-the experimental range and level of the independent variables.

Adsorption isotherms and kinetics
The adsorbent capacity could be described using sorption isotherm. In the present study the adsorption data of phenol were evaluated by Langmuir and Freundlich isotherms. The linear Langmuir isotherm presented as follow: Where the C e is equilibrium concentration (mg/l), q e is phenol adsorbed at equilibrium (mg/g), q 0 and b are the Langmuir constants related to the capacity and energy of adsorption, respectively [20,21].
Freundlich adsorption isotherm is an empirical expression that describes adsorption on a heterogeneous surface. The linear Freundlich isotherm could be illustrated as fallow: Where K f and n are Freundlich constants corresponded to adsorption capacity and adsorption intensity, respectively [22][23][24]. The kinetics were investigated via adsorption of certain concentration of phenol at different contact time. Kinetic study is essential for provide information on the factors affecting it reaction speed.