Project Dissertation Submitted to Universiti Teknologi PETRONAS Chemical Engineering Program In partial fulfillment of the requirement for. Metal ions such as copper, zinc, and lead are loaded into the pores of the modified cellulose so that the positively charged metal ions will capture the slightly polar sulfur atom of dibenzothiophene, removing the organosulfur and toxicity due to the benzene ring. Sorption processes of heavy metals on modified cellulose were carried out in batch mode by changing the contact time, the initial metal concentration and the pH of the solution.
The samples were tested with Atomic Absorption Spectrum analyzer to measure the concentration of adsorbed metal ions. Mohd Shahid Nazir as my mentor in helping me construct experiments procedure and sharing his thoughts in characterization of modified cellulose. 14 Adsorption of heavy metals at different contact times 33 15 Adsorption of heavy metals with different initial metal ion concentration 34.
17 Langmuir isotherm models for the adsorption of heavy metal ions 38 18 Freundlich isotherm models for the adsorption of heavy metal ions 40 19 Temkin isotherm models for the adsorption of heavy metal ions 42 20 Pseudo 1st order models for the adsorption of heavy metal ions 45 21 Pseudo 2nd order models for ions adsorption of heavy metals 46. 1 Mass fraction of carbon and oxygen in cellulose 25 2 Isotherm constants for adsorption of heavy metal ions 43 3 Pseudo 1st order and pseudo 2nd order parameters for heavy metal ions.
INTRODUCTION 1
Background of Study 1
The current method of hydrotreatment has major challenges in terms of energy, cost and efficiency. i) The cost of purchasing and maintaining a modern catalyst is unacceptably expensive. Research on oil desulfurization is essential especially with regard to the economic and environmental impact of the process. Catalysts can only be used when most of the sulfur compound and H2S have been removed from the process stream.
Sulfur removal reaction can be achieved by biocatalytic desulfurization (BDS), where organosulfur is removed from the crude oil fraction using bacteria without breaking down the carbon skeleton of the organosulfur compounds. To enable this process, the surface area of the matrix must be large enough to allow the diffusion of metal ions on the surface. It is one of the most important chemical compounds in the history of human culture.
After crude palm oil (CPO) processing, the residue is treated as biomass waste, including trunks, pulp and empty fruit bunch (EFB). Samples of treated pulp are analyzed by scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) and X-ray dispersion (XRD) to study fiber structure. Relatively comparing the overall structure, the surface of the samples becomes rougher and more irregular from cellulose acetate to EDTA cellulose due to the swelling effect of cellulose after grafting with the carboxyl group.
An increase in the porous structure will promote the diffusion of metal ions due to the increased surface area. The main compositions of the samples are carbon and oxygen, with data shown in Table 1. The reason for the rate reduction is due to the fact that there are a large number of vacant active locations available in the initial phase, and the availability of these locations decreases as the position increases. of time.
Langmuir models for the adsorption of all metal ions on cellulose modified with oxalic acid and EDTA. Freundlich models for the adsorption of all metal ions on cellulose modified with oxalic acid and EDTA. Temkin models for the adsorption of all metal ions on cellulose modified with oxalic acid and EDTA.
A plot of t/q versus t should give a linear relationship, from which qe and k2 can be determined from the slope and intercept of the plot (Figure 21). Pseudo first-order models for the adsorption of all metal ions on cellulose modified with oxalic acid and EDTA. Pseudo second-order models for the adsorption of all metal ions on cellulose modified with oxalic acid and EDTA.
Pseudo 1st order and pseudo 2nd order parameters for heavy metal ion adsorption in cellulose EDTA.
Objective 2
Research Methodology 16
The next stage is the loading of metal ions of copper, lead and zinc into the treated threads. Images of the fibers before and after treatment are analyzed to ensure that the metal ions are distributed through the cellulose pores. The graphs below showed the elemental composition of cellulose acetate, oxalic cellulose and EDTA cellulose.
The crystal lattices of cellulose samples are identified using X-ray diffraction analysis, with results collected in the 2θ range from 2ο to 70ο. It can be seen from the figures below that the adsorption of metal ions shows rapid diffusion to the active site of cellulose, but gradually decreases over time. The adsorption is difficult due to the lower concentration gradient of metal ions and repulsive forces between solute molecules on the solid and bulk phase.
The adsorption of metal ions into cellulose active sites increases almost linearly up to 60 ppm concentration before gradually decreasing the rate at 80 and 100 ppm. The initial concentration of metal ions provides important driving force to overcome the mass transfer resistance between aqueous and solid phases, proving that higher initial concentration increases the adsorption rate. As a result, the electrostatic interaction between the adsorbent and the metal ions caused them to be in mutual repulsion, which caused the adsorption to be low.
The electrostatic interaction between the adsorbent functional group and the solvent achieves mutual affinity, thus allowing more metal ions to bind to the active sites. However, when the pH is above optimum, the tendency of the metal ions to hydrolyze and polymerize will dominate the rate of diffusion into the active sites. Correlation coefficient (R2) values of 1 indicated that the adsorption data of heavy metal ions on cellulose acetate OPEFB fitted well with the Langmuir isotherm.
From Table 2, Freundlich adsorption isotherm model gave the best fit as indicated by higher R2 values for all heavy metal ions compared to Langmuir and Temkin adsorption isotherm models. Pseudo-first-order and pseudo-second-order parameters for the adsorption of heavy metal ions on oxalic cellulose. From this table it can be seen that the adsorption of all heavy metal ions followed the pseudo second order kinetic model due to the higher R2 value.
Celluloses loaded with metal ions are able to remove sulfur due to the presence of the cation from the metal ions that bind to the anion from sulfur compared to cellulose without metal ion loading. From Figure 23, the carbon element has shown an increase in weight percentage after treatment with cellulose loaded with metal ions. Cellulose treated with metal ion loading will create a polar cellulose structure that is capable of adsorbing the slightly polar DBT organosulfur in the petroleum composition.
Optimization of the desulfurization process can be achieved by changing the batch treatment time and increasing the concentration of metal ions in the treated pulp.
