This is to prove that the thesis titled "Batch and column studies on metal removal/uptake under uncontrolled/controlled pH conditions by granular activated alumina from mono, binary and ternary metal ion systems of Cu(II), Pb( II) and Cr(III) at Fixed Total Initial Concentrations” submitted by Patil Ravindra Jaysing Registration no.
List of Tables
List of Abbreviations/Notations
TQe,exp : Experimental total metal removal at equilibrium Tqe,exp : Experimental total metal uptake capacity.
Abstract
INTRODUCTION
Kinetics of metal biosorption from the binary metal ion system composed of Cr(VI) and Fe(III) to C. Further these studies have failed to investigate the simultaneous biosorption of metal ions from the binary metal ion system. Kinetics of metal uptake was investigated by mono-metal ion systems of Cd(II) and Ni(II) in bagasse fly ash (Srivastava et al., 2006).
Furthermore, simultaneous adsorption of both metal ions from the binary metal ion system may have occurred on the adsorbent.
LITERATURE REVIEW
Single component adsorption isotherm models
In the case of liquid phase adsorption, especially in heavy metal adsorption using biosorbent, this model falls short in representing the equilibrium data (Febrianto et al., 2009). This model is very popular for predicting heavy metal biosorption equilibrium data (Febrianto et al., 2009). Toth isotherm model (Table 2.1) is another empirical equation developed to improve Langmuir isotherm fittings (Toth, 1971) and useful in the description of heterogeneous adsorption systems, while satisfying both low and high-end limit of the concentration ( Vijayaraghavan et al.), 2006. .
Equilibrium biosorption of Cd(II) and Cu(II) metal ions was investigated using wheat straw as an adsorbent (Dang et al., 2009).
Competitive isotherm models
The modified competitive Langmuir model approach provided excellent prediction of the binary adsorption data of Cu(II)-Cd(II), Pb(II)-Cd(II) and Pb(II)-Cu(II) on calcium alginate grains ( Papageorgiou et al., 2009). All parameters of the extended Langmuir model were estimated from the equilibrium data of three metals. Also in this study, the total initial metal ion concentration in single-component systems was different from that in multi-component systems.
Equilibrium uptake of Cr(VI) and Ni(II) in the binary mixture was found to decrease as a result of the levels of Cr(VI) and Ni(II) concentrations due to the antagonistic interaction between the components.
Kinetics of heavy metal adsorption
Pseudo-second-order kinetic model: Predicting the adsorption rate for a given system is among the most important factors in designing an adsorption system, since the kinetics of the system determine the adsorbate retention time and reactor dimensions. The pseudo-second-order model is derived based on the sorption capacity of the solid phase (Ho, 2006), expressed as In general, adsorption involves 4 basic steps, namely: (1) transfer of adsorbate from the base solution to the boundary film, (2) transfer of adsorbate from the boundary film to the adsorbent surface (external mass transfer step), (3) transfer of adsorbate from the adsorbent surface to of the active site or binding site within the particles (intraparticle diffusion rate) and (4) adsorbate adsorption on the active or binding sites of the adsorbent.
The linear region of the curve was selected for fitting to the model using linear regression analysis, where the slope and intercept represented KWM and I, respectively.
Multi-component kinetic studies
However, this decrease in adsorption rates for metal ions can be attributed to the different concentration gradient that existed in mono and binary metal ion systems for a fixed number of adsorption sites. Since the study was conducted on a 'mg' basis in binary metal systems and it is well known that adsorption of metal ions is done on a mole or equivalent basis, moles or equivalents of 1 mg/L concentration of a particular metal ion is not equal to 1 mg/L of other metal ions, i.e., the concentration gradient created by Cr(VI) and Fe(III) metal ions will be different due to their different molecular weights and valences. This decrease in adsorption capacities for Cd(II) metal ions can be attributed to the different concentration gradient that existed in the mono and binary metal ion systems for a fixed number of adsorption sites.
Since the study was carried out on the basis of 'mg' in binary metal systems and it is well known that the adsorption of metal ions takes place on a mol or.
Column studies
Additionally, mono- and multi-metal ion system column studies have been performed with different total initial metal ion concentrations in influent solution. Additionally, mono- and multi-metal ion system column studies have been performed with different total initial metal ion concentration in influent solution on a mass basis. Mono- and multi-metal ion system column studies have been performed with different total initial metal ion concentration in influent solution on a mass basis.
The study elucidated the effect of bed depth, flow rate and initial metal ion concentration on the breakthrough curves. the residence time increased and the breakthrough curve shifted to the right.
Concluding remarks
However, this study also failed to investigate the overall adsorption capacities under fixed total initial concentration of metal ions in mono- and multi-metal systems. Similarly, the main focus of column studies of multi-metal ionic systems was to compare the detection curves of metal ions from multi-metal ionic systems with mono-metal ionic systems and finally based on the results the competition between metal ions for adsorption sites. However, little literature is available describing the adsorption of various metal ions on the already depleted column bed and thus the possible migration of the already adsorbed metal ion back into the flow solution.
Furthermore, fewer literatures are available describing the working pH conditions and also the variation in pH during the adsorption process, which is very essential to describe the exact process of metal ion removal, i.e. by adsorption or combined effects of precipitation and adsorption. .
OBJECTIVES AND SCOPE OF THE WORK
To investigate equilibrium studies of metal removal under uncontrolled pH conditions and metal uptake under controlled pH conditions from mono-, binary and ternary metal ion systems with fixed total initial metal ion concentration in solution on an equivalent basis. To investigate column studies of metal removal from mono- and binary metal ion systems with fixed total initial metal ion concentration in solution on an equivalent basis under uncontrolled and controlled pH conditions. The study includes assessing (i) the variation in pH of wastewater exiting the column beds, (ii) additional metal removal potential of depleted bed if refilled with another metal ion, and (iii) migration of previously removed metal ion from bed into the effluent, if any (iv) total metal removal from mono and binary metal ion systems.
MATERIALS AND METHODS
- Materials
- Methods
- Metal ions availability in aqueous phase with variation in solution pH from mono-, binary- and ternary-metal ion systems comprising of Cu(II), Pb(II) and
- Effect of contact time on metal ion concentration remaining in aqueous phase under uncontrolled and controlled pH conditions from mono-, binary- and
- Kinetics of metal removal under uncontrolled pH conditions and metal uptake under controlled pH conditions from mono-, binary- and ternary-metal ion
- Batch tests to investigate additional metal removal under uncontrolled pH conditions and additional metal uptake under controlled pH conditions by GAA
- Kinetics of metal removal under uncontrolled pH conditions and metal uptake under controlled pH conditions for four loading cycles with mono- and binary-
- Equilibrium studies for metal removal under uncontrolled pH conditions and metal uptake under controlled pH conditions from mono-, binary- and ternary-
- Continuous mode column studies for metal removal under uncontrolled and controlled pH conditions from mono- and binary-metal ion systems comprising of
- Estimation of pH zpc of GAA
- Estimation techniques used
The four different combinations of the binary-metal ionic system of Cu(II)+Pb(II) based on different desired initial concentration of metal ions were (a) 0.45 meq/L Cu(II). Details of selected combinations of mono-, binary- and ternary metal ion systems with unique designations are shown in Table 4.5. Equilibrium studies were carried out under uncontrolled and controlled pH conditions by combinations of mono-, binary- and ternary metal ion systems composed of Cu (II), Pb (II) and Cr (III) ions.
The column studies were conducted for metal removal from combinations of mono- and binary metal ion systems under uncontrolled and controlled pH conditions.
RESULTS AND DISCUSSION
Metal ions availability in aqueous phase with variation in solution pH from mono-, binary- and ternary-metal ion systems comprising of Cu(II), Pb(II) and
The metal availability in aqueous phase from mono-, binary and ternary metal ion systems comprising Cu(II), Pb(II) and Cr(III) metal ions was studied with variation in solution pH. Furthermore, the availability of Cu(II), Pb(II) and Cr(III) metal ions in the aqueous phase was reduced to 2%, 82% and 5%, respectively, at pH 5.50. The availability of Cu(II), Pb(II) and Cr(III) metal ions in aqueous phase from mono-, binary and ternary metal ion systems with variation in solution pH is shown in fig.
The availability of metal ions in aqueous phase with variation in solution pH from mono-, binary and ternary metal ion systems was experimentally investigated.
Effect of contact time on metal ion concentration remaining in aqueous phase under uncontrolled and controlled pH conditions from mono-, binary- and
The effect of contact time on the concentrations of metal ions remaining in the aqueous phase from binary-metal ion systems consisting of Cu (II) + Pb (II) were investigated under uncontrolled and controlled pH conditions. The effect of contact time on the concentrations of metal ions remaining in the aqueous phase from binary metal ion systems consisting of Cr(III)+Pb(II) were investigated under uncontrolled and controlled pH conditions. The effect of contact time on the concentration of residual metal ions in the aqueous phase from binary metal ion systems consisting of Cu (II) + Cr (III) was investigated under uncontrolled and controlled pH conditions.
The residual concentrations of both Cu(II) and Cr(III) metal ions remaining in the aqueous phase decreased simultaneously by binary metal ion systems under uncontrolled and uncontrolled conditions.
Kinetics of metal removal under uncontrolled pH conditions and metal uptake under controlled pH conditions from mono-, binary- and ternary-metal ions
The kinetics of metal uptake under controlled pH conditions and metal removal (or reduction) under uncontrolled pH conditions have been studied with mono-, binary and ternary metal ion systems consisting of Cu(II), Pb(II) and Cr(III). ) metal ions in the present work. The kinetics of metal removal under uncontrolled pH conditions and metal uptake under controlled pH conditions from monometallic ion systems of M[Cu(0.60)], M[Pb(0.60)]. The experimental total metal removal (TQt) under uncontrolled pH conditions and the experimental total metal uptake (Tqt) under controlled pH conditions from three combinations of binary metal ion systems with a fixed initial total metal ion concentration of 0.60 meq/L are shown in Table 5.5.
Changes in Cu(II) and Pb(II) metal removal under conditions of uncontrolled pH and.
