Tag Archives: Thermodynamic

Using Modified Nano- Hydroxyapatite for Removing Iron Ions Contaminants from Groundwater (Published)

In this article, concentrate about altered nano-hydroxyapatite (HAp) by nano-manganese oxide (Mn3O4) as adsorbent material to expel iron particles from ground-water. Various parameters were concentrated to choice ideal states of evacuating, for example, contact time, pH, beginning fixation, a measurement of adsorbent, disturbance speed and temperature. Energy studies included first request (R2 = 0.95), pseudo-first-request (R2 = 0.936), second-request (R2 = 0.98), pseudo-second-request (R2 = 0.99), Elovich condition model (R2 = 0.97), intraparticle dissemination (R2 = 0.96), Natarajan and Khalaf (R2 = 0.91) were completed, the acquired outcomes uncovered that the pseudo-second-request is the best to portray the adsorption procedure on the grounds that the connection coefficient is moving toward one (R2 = 0.95). Adsorption isotherm was determined by utilizing Freundlich, Langmuir and Temkin constants, adsorption limit from the Langmuir model was 0.606 mg/g. Thermodynamic parameters (ΔG, H = −55 KJ/mol, and S = −152 (KJ/mol)) for the adsorption procedure were additionally determined and talked about.

Keywords: Adsorption, Groundwater, Hydroxyapatite, Iron Ions, Kinetic, Manganese Oxide, Nano Materials, Thermodynamic


The use of low-cost, locally available and eco-friendly adsorbents has been investigated as an ideal method of controlling waste. In this paper,activated Delonix regia leaves(DRL), Delonix regia tree bark(DRB) and combined Delonix regia leaves and bark (DRBL) have been used as biosorbents for the removal of Chromium (VI) from aqueous solutions. The biosorption studies were carried out using each biosorbent singly and the combination of the two in equimolar proportions respectively. The concentrations of the metal ions uptook were determined by atomic absorption spectroscopic (AAS) method. Biosorption experiments were performed as a function of pH, contact time, particle size, biosorbent dosage, temperature, initial concentration of the biosorbate. The maximum removal of chromium(VI) was obtained at pH 2 after two hours. Kinetics data obtained in this study fitted satisfactorily to the pseudo-first-order rate equation for all the biosorbents, suggesting that the biosorption process is chemisorption. The experimental equilibrium data were tested for Langmuir and Freundlich models, and the Freundlich model fitted better for all the biosorbents with correlation coefficient (R2) ranges 0.997 – 0.999. Thermodynamic parameters such as Gibbs free energy, enthalpy and entropy evaluated from experimental data predict the nature of the uptake, revealed that uptake of Chromium (VI) was endothermic at 25 0 C. The results show that a large proportion of Chromium (VI) was uptook at higher percentage when the combined form of the biosorbents was used as compared to when the biosorbents were used singly.

Keywords: Chromium(VI), Delonix regia, Isotherm, Kinetics, Thermodynamic, Uptake