Scale-Up Production of Palm-Based Wax Esters Using Lipozyme Rm Im and Characterisation of the Esters

The investigation of palm-based wax esters synthesis was started in a 1-L scale stirredtank reactor (STR) with 0.5-L working volume using Rushton turbine impeller. The optimum alcoholysis conditions derived from the Response surface methodology (RSM) were: temperature 50.4°C, amount of enzyme 16 wt% of palm oil, amount of palm oil 200 mmol, amount of oleyl alcohol 600 mmol, palm oil-to-oleyl alcohol ratio 3:1 and impeller speed 242 rpm. The corresponding predicted value of percentage yield and productivity were 91.5% and 106.4 mmol/h respectively as compared to the actual experimental value of 92.3% and 110.8 mmol/h. The optimum reaction condition derived from RSM was employed in the 1.5-L STR. Rushton turbine (RT), AL-hydrofoil (AL-H) and 2-bladed elephant ear (EE) impeller were used to investigate the mixing performance in the reactor. Of these impellers, RT was found to give the highest reaction yield of 95.8% and productivity of 344.9 mmol/h at lower agitation speed (250 rpm) as compared to the other two impellers. Homogeneous solid suspension was achieved by RT impeller at 250 rpm with almost 99% solid suspension height. The shortest mixing time was obtained by the agitation system with 2-bladed EE impeller due to the larger Di/Dt ratio of the impeller. For all the impellers tested, the Reynolds number obtained were in the range of 102 <Re< 104, indicated that the fluid flow pattern fell in the transition region for the agitation range tested. Although ruptures and cracks of immobilised enzymes were observed in the agitation system, the high stability of Lipozyme RM IM was proven by its reusability of more than fifteen times under agitation system of RT impeller, to give reaction percentage yield of 78.9%, which was only 16.9% reduced from the first cycle. Subsequently, scale-up production of palm oil esters (POE) to 50-L was successfully carried out in the 75-L STR based on constant impeller tip speed method. The esters yield and productivity were increased to 97.2% and 11.67 mol/h, respectively. Higher reaction rate was observed in the 50-L scale production with the reaction equilibrium achieved earlier at 4 h of reaction time as compared to the 5 h optimum reaction time observed in bench-scale study. The esters yield and productivity were not only maintained during the scaling-up study, but increased gradually from reaction of 0.5- L, 1.5-L to 50-L. Analyses of palm-based wax esters were carried out to establish compliance to product specifications and standards. Important physicochemical properties were analysed followed a standard Test Methods modified from American Oil Chemists’ Society (AOCS) as well as Malaysian Palm Oil Board (MPOB) standard. Simultaneous differential scanning calorimetry-thermal gravimetry analysis (DSC-TGA) showed high thermal stability profile of palm-based wax esters. The dermal irritation assay of POE showed the non-irritancy of the esters with Human Irritancy Equivalent (HIE) score below 0.9; whilst an increase of skin hydration of 40.7% after 90 min application was achieved in the acute moisturising test. Downstream processing of POE was carried out using liquid-liquid extraction and crystallisation process to remove the remaining reactants including oleyl alcohol and lipids impurities in the esters. Ethanol was used as the solvent to remove the remaining unreacted oleyl alcohol in the POE mixture. The extraction was carried out in separatory funnel with optimum ethanol to esters ratio 4:1 at room temperature. A removal of 97% of the unreacted oleyl alcohol was achieved after 3 stages of extraction with 30 min contact time for each stage at 150 rpm agitation speed of the water bath shaker. Meanwhile, crystallisation of POE mixture at 23°C for 24 h incubation time was shown to increase the purity of the esters from 92.0% to 96.1%

Low Cost Adsorbents for Sustainable Dye Containing-Wastewater Treatment

Dyes are coloured substances that can be applied to various substrates such as textile materials, leather, paper and hair. The usage of dyes has continuously increased in many industries but the removal of this pollutant remains as a problematic issue as they are generally stable to light and oxidizing agents and are resistant to aerobic digestion. This literature review paper provides and lists several low cost adsorbents to serve as an alternative method for dye removal. Adsorption using low cost materials can be viewed as a sustainable treatment process because most of these materials are of naturally occurring, locally available and inexpensive materials. This paper covers an overview of dyes waste treatments for 5 years period, from 2008-2012. Some of the noteworthy adsorbents include agricultural byproducts, industrial waste and natural clay materials. Besides, the combination processes involving adsorption and other methods was also discussed

Removal of dyes from wastewaters by low-cost adsorbents

Dyes represent an objectionable pollutant to the environment. The removal of dyes has been of great concern because of their toxicity and persistency. The usage of commercial activated carbon to remove dyes in wastewater is limited due to its high cost. This prompted the search for alternative low-cost adsorbents. This chapter examines (i) historical aspects and pollution issues concerning dyes; (ii) main treatment technologies and their limitations; (iii) various studies using waste materials from agriculture and industry or naturally occurring biosorbents; and (iv) equilibrium and kinetic models used in batch and continuous systems that are important for design purpose

Utilization of Fruits Peel as A Sorbent for Removal of Methylene Blue

The potential of using fruits skin as a low cost sorbent in the removal of methylene blue from aqueous solution was studied. The sorption behaviour of various fruits skin for methylene blue was carried out as a function of pH, contact time, concentration of methylene blue and sorption isotherms. The sorption process was rapid with high percentage of uptake taking place within the first 1 h, regardless of its initial concentration. Different kinetic models were selected to interpret the experimental data. The sorption process conformed to Langmuir isotherm and maximum sorption capacities for methylene blue were 56.50, 34.97, 50.51, 48.54, 48.31 and 78.74 mg/g for mangosteen\u27s analyze and explain experimental data obtained. It was found that application of pseudo-second order kinetics provides better correlation of the experimental data than the pseudo-first order model for the different systems studied

Tartaric Acid Modified Rice Hull as a Sorbent for Methylene Blue Removal

Problem statement: Improper dye discharge from various industries such as textile, paper, cosmetic and plastics into receiving streams can be one of the sources towards water pollution. The release of these effluents not only causes various disruptions in the ecosystems, but also poses hazard effect as most of the dyes are highly toxic, mutagenic and carcinogenic in nature. Approach: To prepare an inexpensive and efficient sorbent by chemically modifying rice hull for the removal of Methylene Blue (MB) which is predominantly used in coloring acrylic fiber. Batch experiments were carried out for the removal of MB from aqueous solution by using Tartaric Acid Modified Rice Hull (TARH). Parameters studied include effect of pH, contact time, initial dye concentration and agitation rate and sorption isotherm. Results: From the results, the percentage uptake of MB increased with increasing contact time and agitation rate. Based on the linear regression correlation coefficient, R2, the system under study is more appropriately described by the pseudo-second order model. Maximum sorption capacity calculated from the Langmuir model is 25.0 mg g-1 for MB. Conclusion: The study has shown the effectiveness of TARH in the removal of MB, a basic dye from synthetic solutions. © 2010 Science Publications

Removal of Hazardous Heavy Metals From Aqueous Environment by Low-Cost Adsorption Materials

The rapid growth of the human population and industrialization in the world has indirectly increased environmental problems such as water, air and land pollution. Amongst all, heavy metals can be considered as the most problematic pollutants. Numerous efforts have been attempted to minimize the impact of heavy metals. This chapter discusses the recent developments and technical applicability of different treatment methods for heavy metal removal. The adsorption process using various low-cost materials as the potential alternative for heavy metal removal is being highlighted and summarized

Equilibrium Studies for the Removal of Basic Dye by Sunflower Seed Husk (Helianthus annuus)

The sorption characteristics of sunflower (Helianthus annuus) seed husk (SSH) to remove Methylene Blue (MB) from aqueous solution under batch conditions have been investigated. Sorption of MB was found to be pH, concentration and agitation dependent. The kinetics of sorption was rapid with 80% sorption taking place within the first 60 min regardless of its initial concentration. The fast attainment of equilibrium implying the biosorbent could be suitable for continuous flow system. Using the pseudosecond order kinetics model, the predictive model for MB sorbed at time t (qt) with the initial concentration of (Co) is given by qt = Cot/[0.0607Co + 2.0762 + (0.0012Co + 5.1949)t]. Results indicated that the predicted uptakes of MB agreed closely with experimental values obtained. The experimental data fitted well to Langmuir isotherm model with the correlation coefficient of 0.9860 and maximum monolayer sorption capacity of 45.25 mg/g

Dye Waste Treatment

© 2011 by the authors. Dye wastes represent one of the most problematic groups of pollutants because they can be easily identified by the human eye and are not easily biodegradable. This literature review paper highlights and provides an overview of dye waste treatments performed over the three years period from 2008-2010. Noteworthy processes for the treatment of dye waste include biological treatment, catalytic oxidation, filtration, sorption process and combination treatments

Utilization of Fruits Peel as A Sorbent for Removal of Methylene Blue

The potential of using fruits skin as a low cost sorbent in the removal of methylene blue from aqueous solution was studied. The sorption behaviour of various fruits skin for methylene blue was carried out as a function of pH, contact time, concentration of methylene blue and sorption isotherms. The sorption process was rapid with high percentage of uptake taking place within the first 1 h, regardless of its initial concentration. Different kinetic models were selected to interpret the experimental data. The sorption process conformed to Langmuir isotherm and maximum sorption capacities for methylene blue were 56.50, 34.97, 50.51, 48.54, 48.31 and 78.74 mg/g for mangosteen\u27s analyze and explain experimental data obtained. It was found that application of pseudo-second order kinetics provides better correlation of the experimental data than the pseudo-first order model for the different systems studied

Papaya (Carica Papaya) Seed as a Low-cost Sorbent for Zinc Removal

The potential of using papaya seed as a sorbent for the removal of Zn from aqueous solution was investigated. The sorption characteristics of the sorbent was studied under various experimental conditions, such as pH, contact time, concentration of Zn(II), agitation rate and sorbent’s particle size. The equilibrium data have been studied using Langmuir, Freundlich and Brunauer-Emmett-Teller equations. The best correlation was obtained using Langmuir isotherm with the regression coefficient value of 0.9799 and maximum sorption capacity of 19.88 mg/g. The effective pH for the maximum uptake of Zn(II) was at pH 5.0. An increase in percentage uptake of Zn(II) can be observed with increasing contact time and agitation rate. Decrease in sorbent particle size led to an increase in the sorption of Zn(II) and this could be explained by an increase in surface area and hence binding site. Equilibrium was attained around 60 min indicating this sorbent could be a potential material for continuous flow system