Experimental dataset on acid treated eggshell for removing cyanide ions from synthetic and industrial wastewaters

The data current in this article are associated to the efficacy of acid treated eggshell as eggshell membrane (ESM) as an adsorbent for eliminating cyanide ion from synthetic and industrial wastewaters. This article describes the effects of selected factors such as pH (3–11), contact time (5–60 min), cyanide ion concentrations (50–150 mg/L), ESM dose (0.25–2 g/L), and solution temperature (20–50) on the removal cyanide ion from aqueous solution. The maximum cyanide ion removal obtained at a solution pH of 9–11. The kinetic data agreed with the pseudo-second-order kinetic. The equilibrium adsorption data at different temperatures well set through Langmuir equation. FTIR and thermodynamic data describe main adsorption phenomenon in cyanide ion onto ESM could be the ion exchange and chemisorption.


a b s t r a c t
The data current in this article are associated to the efficacy of acid treated eggshell as eggshell membrane (ESM) as an adsorbent for eliminating cyanide ion from synthetic and industrial wastewaters. This article describes the effects of selected factors such as pH (3)(4)(5)(6)(7)(8)(9)(10)(11), contact time (5-60 min), cyanide ion concentrations (50-150 mg/L), ESM dose (0.25-2 g/L), and solution temperature (20-50) on the removal cyanide ion from aqueous solution. The maximum cyanide ion removal obtained at a solution pH of 9-11. The kinetic data agreed with the pseudo-second-order kinetic. The equilibrium adsorption data at different temperatures well set through Langmuir equation. FTIR and thermodynamic data describe main adsorption phenomenon in cyanide ion onto ESM could be the ion exchange and chemisorption.
& 2017 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Value of the data
The data presents a low -cost adsorbent make from waste material of eggshell membrane. The isotherm, kinetic and thermodynamic data will be useful and valuable for expecting and modeling the adsorption capacity and mechanism of cyanide ion elimination via the adsorbent. The attained data will be beneficial for the methodical and engineering community that needing to scale up and design an adsorption column with eggshell membrane as bed for the elimination of cyanide ion from water or wastewater.

Data
SEM data for eggshell membrane with different magnification were shown in Fig. 1a, b. Fig. 2a, b displayed EDX spectra data of the fresh eggshells and ESM. Fig. 3 indicated experimental data for point of zero charge (pHzpc) of ESM. Fig. 4 depicted data for the FTIR spectrum of ESM before and after cyanide loaded. Data of the influence of solution pH on cyanide ion removal by ESM is shown in Fig. 5. In Fig. 6 the profile of cyanide removal data as a function of ESM dosage indicated. Fig. 7 demonstrated data of intraparticle diffusion model plot for the adsorption of cyanide onto ESM through different concentrations. Fig. 8 showed the profile of cyanide ion removal data as a function of solution temperature. The parameters obtained from pseudo-first -order model parameters with different initial cyanide ion concentrations are tabulated in Table 1. The parameters obtained from pseudo-second-order model parameters with different initial cyanide ion concentrations indicated in Table 2. The parameters obtained from intraparticle diffusion model with different initial cyanide ion concentrations exhibited in Table 3. In Table 4 the data regarding to Langmuir, Freundlich, Dubinin-Radushkevich and Temkin adsorption isotherm parameters are presented. Thermodynamic data for adsorption of cyanide ion on ESM indicated in Table 5. Table 6 described the quality of electroplating plant wastewater before and after treatment with the ESM.

Materials
In this work, fresh eggshells used were obtained from local confectionary shop. The eggshells were initially washed with tap water and then dried at 105°C. The dried eggshells were grinded to size 0.5-0.6 mm. To prepare ESM, the eggshells were occupied in the hydrochloric acid (%0.5) for 35 min [1]. The obtained ESM were washed with distilled water and washed ESM was dried in the oven at 80°C. The stock of cyanide solution (1.0 g CN − /L) was prepared by dissolving required quantity of NaCN in 1.0 L of Milli-Q water. All of chemicals and reagents were of analytical grade that were used without further purification (Merck Co., Germany).

Adsorption tests
The ability of ESM to the cyanide removal was assessed by a series of batch experiments in a shaker-incubator instrument (Pars Azma Co, Iran). For each experimental run, 100 mL of solution having a known concentration of cyanide ion and with the chosen level of pH was first poured into beaker. Then, a fixed mass of ESM was added to vessel and placed inside the shaker-incubator. Next, vessel was mixed at 120 rpm for a given time. Lastly, the suspension of shacked sample was filtrated and analyzed for the concentration remained cyanide ion. The influence of temperature, pH, mixing time, initial cyanide ion concentration and adsorbent mass as variable parameters assessed. Eqs.
(1) and (2) were used to determine the cyanide removal efficiency (R) and the adsorption capacity of ESM in each run [2,3].
where C 0 and C e are the initial and equilibrium concentration of cyanide ion, respectively; q e is equilibrium cyanide concentration on ESM, V is the volume of solution and M is the mass of the used ESM sample.

Analysis and characterization
Chemical composition ESM was investigated using a Philips model XL-30 scanning electron microscope (SEM) with energy-dispersive X-ray microanalysis (EDX). The pH of point of zero charge (pHpzc) for ESM was measured by the method described by Asgari et al. [4]. Fourier transform infrared (FTIR) spectroscopy (Perkin-Elmer spectrophotometer spectrumone) in the range, 450-4000 cm -1 was used to investigate of functional groups on the surface of ESM. The concentration of cyanide ion was determined according to standard method 4500-CN-D of APHA [5].

Isotherm of cyanide ion adsorption onto ESM
To describe the cyanide adsorption capacity data, obtained isotherm data were fitted by four most commonly used isotherms including Langmuir, Freundlich, Dubinin-Radushkuvich and Temkin. The linear forms of apply isotherms equations can be represented respectively as bellow [5]: Langmuir equation :   where q e and C e are parameters that are described in Eqs. (1) and (2). K and n are constants that indicate the adsorption capacity and the adsorption intensity. q max is the maximum amount of adsorption (mg/g) and b is the adsorption equilibrium constant (L/mg). B ¼ RT b , T is the absolute temperature in K and R is the universal gas constant in (J/mol K). Ɛ (Polanyi potential) is RT ln(1þ (1/C e ), q max the adsorption capacity (mg/g), k a constant related to adsorption energy, R and T are the gas constant and temperature (K). R L equilibrium constant obtained as follows [5][6][7]: where C 0 is the initial concentration of cyanide ion. k as energy adsorption, calculated from the k value using the following equation:

The kinetic study
To investigate the adsorption mechanism of cyanide removal, the experimental data was fitted with most commonly used pseudo-first-and second-order kinetics model at different experimental conditions. The pseudo first-order kinetic linear equation is generally as follow: where q e;meas and q t are experimentally measured and calculated cyanide adsorbed on ESM at time t, k 1 is the rate constant for pseudo-first-order kinetic. The linear regression analysis of In (q e,meas −q t ) vs t for different experimental conditions will give the data of the q e,calc (q e,calc ¼exp (intercept)) and k 1 (k 1 ¼−(slop)) (8,9). The pseudo second-order kinetic linear equation is generally as follow: The value of q e,calc (q e , calc ¼1/slope) and k 2 as the rate constant (k 2 ¼slope 2 /intercept) of the pseudo-second-order equation obtained from linear regression analysis of t/q t vs t [8][9][10]. Via Weber and Morris equation was also used to evaluate experimental adsorption kinetic data. The linear form of the equation is as follows [11,12]: where C is the intercept and kid is the intraparticle rate constant obtained from the slope of the plot of q t against t 0.5 .

Thermodynamics study
To explain the mechanism of cyanide adsorption onto eggshells, the thermodynamics parameters associated with the adsorption were determined by using following equation [13]: ln

Validity of adsorption isotherm and kinetic study
The applicability of the isotherm equations and kinetic models were evaluated by The correlation coefficient and also comparing residual root mean square error (RMSE) and the chi-square test (X 2 ) (3, 15) which can be described as: The correlation coefficient (R 2 ) and also the average relative error (ARE), the sum of squares error (SSE) and the average percentage error (APE) in the kinetics studies use to the validity of kinetic models data and they were calculating by following Eqs: where q e;meas is the observation from the batch experiment i and N is the number of measurements made. Upon completion of the basic adsorption experiments, data of the efficacy of ESM in the removal of cyanide ion from industrial wastewater was evaluated. For this, a bulk wastewater sample was obtained from a local electroplating plant.