Kinetic Model for pH Variation Resulted from Interaction of Aqueous Solution Contaminated with Nickel Ions and Cement Kiln Dust

Dooraid N Ahmed,Salim H Jassam,Mu Naushad,Laith A Naji,Ayad A H Faisal

doi:10.1155/2020/8732308

Abstract

Reaction term in the transport equation which described the migration of metal ions in the porous medium is frequently represented by conventional kinetic models such as pseudo-first order, pseudo-second order, and others. Unfortunately, these models are applicable for the constant value of solution pH, and they cannot simulate the real situation in the field scale where this pH may be changed with time. Accordingly, the present study is a good attempt to derive the kinetic model that can simulate the change in the pH of the solution through solute transport. This was achieved by modifying the adsorption capacity and reaction constant to be functions in terms of solution pH by using semianalytical analysis and numerical approximation. The results proved that the kinetic model based on the numerical approximation (using exponential functions for adsorption capacity and reaction constant) symbolled as model 2 was more representative from other models applied for the description of interaction of nickel ions (with initial concentration of 400 mg/L) and cement kiln dust with sum of squared error ≤1.54913 and determination coefficient ≥0.889. Also, the developed models had high ability for recognizing between pure precipitation and pure adsorption.

Highlights

Contamination of groundwater and surface water resources due to leakage of heavy metals such as cadmium, lead, mercury, chromium, nickel, zinc, and others from natural and anthropogenic activities are considered serious environmental problem [1,2,3,4,5]
Experimental outputs resulted from interaction of cement kiln dust (CKD) and aqueous solution contaminated with nickel ions are used to verify the derived model
Due to the complexity of the phenomenon under consideration and to express of the sorption performance, the numerical model was utilized to simulate the influence of pH. e kinetic model derived previously can be completed by using different numerical simulation functions that are based on the exponential model for representing of and (k1) (Table 2)

Summary

Introduction

Contamination of groundwater and surface water resources due to leakage of heavy metals such as cadmium, lead, mercury, chromium, nickel, zinc, and others from natural and anthropogenic activities are considered serious environmental problem [1,2,3,4,5]. E production of cement material is accompanied with the generation of large quantities of byproduct named cement kiln dust (CKD) It is a heterogeneous fine-grained solid of highly alkaline constituent due to the presence of a greatest percentage of limestone [15, 16]. E major mechanisms responsible of the contaminant transfer during the treatment process due to the interaction of cement kiln dust (CKD) and aqueous solution contaminated with heavy metals have been proved in the previous studies. The pH of the contaminated water can be increased dramatically with the presence of CKD due to the high lime content and, metal hydroxide can be formed [21,22,23] There is another mechanism rather than the pure adsorption which governed the treatment process which known as “pure precipitation.”. Experimental outputs resulted from interaction of CKD and aqueous solution contaminated with nickel ions are used to verify the derived model

Derivation of Kinetic Model for CKD-Metal Ions Interaction

Materials and Methods

Results and Discussion

Model Model 2