Elvis Nam | Heriot-Watt University (original) (raw)

Papers by Elvis Nam

Research paper thumbnail of Application of response surface analysis for optimization of dyes sorption onto EDTA modified rice hull

The batch removal of basic and reactive dyes from aqueous solution using ethylenediamine tetraace... more The batch removal of basic and reactive dyes from aqueous solution using ethylenediamine tetraacetic acid modified rice husk (ERH) was studied. Plackett-Burman design coupled with response surface methodology (11SM) were adopted to evaluate the effect of various operating parameters, such aspH (2-10), contact time (5-420 mins) andsorbent dosage (0.05-0.2 g) on the percentage of dye removal. The optimum adsorption conditions for Methylene Blue were determined as pH: 8.6, contact time: 131 mins and sorbent dosage: 0.13 g. As for Reactive Orange 16, a greater uptake was observed at a lower pH. The empirical model developed from the interactive effects of important operating variables was validated using ANOVA analysis. The percentage uptakes predicted by the model are in good agreement with the experimental values, thus confirming the reliabilily of the models.

Research paper thumbnail of Synthesis and characterization of new Schiff base ester liquid crystals with fatty acids from palm oil as flexible alkyl chain

Industrial Crops and Products, 2021

Research paper thumbnail of Optimization of basic and reactive dye uptakes in binary dye solution using statistical experimental methodology

In the present study, the optimum adsorption conditions for the uptake of methylene blue (MB) and... more In the present study, the optimum adsorption conditions for the uptake of methylene blue (MB) and reactive orange 16 (RO16) in binary dye solution by ethylenediamine tetraacidic acid (EDTA) modified rice hulls was studied. By using the Plackett-Burman design, the significant variables in affecting the MB and RO16 uptake in binary dye solution were identified as pH and contact time. The combined effects of interaction between the variables were determined using response surface methodology (RSM). The model predicted that at optimum conditions: pH 6.77 and contact time of 205.58 min, the MB uptake greater than 95% could be obtained. As for RO16, the RSM indicated that pH 3.17 and contact time of 205.59 min were optimal for maximum percent dye uptake. These predicted values were also experimentally validated to confirm the reliability of the models.

Research paper thumbnail of Evaluation on the efficiency of ethylenediaminetetraacetic acid (EDTA)-modified rice husk as a low-cost sorbent for various dyes removal under continuous flow condition

Desalination and Water Treatment, 2015

AbstractThe potential of ethylenediaminetetraacetic acid (EDTA)-modified rice husk (ERH) as a sor... more AbstractThe potential of ethylenediaminetetraacetic acid (EDTA)-modified rice husk (ERH) as a sorbent to remove both methylene blue (MB) and reactive orange 16 (RO 16) in single and binary dye solutions was studied. Surface characterization of natural rice husk and ERH was investigated using field emission scanning electron microscope (FESEM) and atomic force microscope (AFM). From the FESEM micrographs, due to the absence of pores and cavities, it can be concluded that ERH is a non-porous material. The adsorption behaviour of MB and RO 16 onto column packed with ERH was investigated under continuous flow mode with three different parameters: the effect of influent concentration, the effect of bed depth and the effect of flow rate. Column studies indicated that the breakthrough time is longer for MB at lower influent concentration and flow rate. Unusual breakthrough curves were obtained for RO 16 in both single and binary dye solutions with very rapid initial breakthrough. This implies that the adsorption...

Research paper thumbnail of Dye Waste Treatment

Research paper thumbnail of Synthesis and characterization of new Schiff base ester liquid crystals with fatty acids from palm oil as flexible alkyl chain

Palm oil plays an important role in both food and non-food industries. With the aim of further di... more Palm oil plays an important role in both food and non-food industries. With the aim of further diversifying the non-food applications of palm oil, the viability of using palm fatty acids in the synthesis of liquid crystals (LCs) has been investigated. In this study, three types of palm fatty acid, namely lauric acid, palmitic acid and stearic acid were used as a source of flexible alkyl chain, which is an influential structural feature of LCs. This flexible alkyl chain is usually derived from non-renewable petrochemicals. Three palm-based LCs (PBLCs), namely, PB 1 (lauric-based LC), PB 2 (palmitic-based LC) and PB 3 (stearic-based LC) have been synthesized and the presence of liquid crystallinity was further verified by Polarizing Optical Microscopy (POM), Differential Scanning Calorimetry (DSC) and Wide Angle X-ray Diffraction (WAXD). Mesophase was observed from POM analysis for PB 1-PB 3 and based on the scattering pattern of WAXD at small angle region, the texture of the mesophase was Smectic A phase. The synthesized PBLCs can be potential candidate for various practical applications such as engineering of nanostructure and biomaterials due to the presence of curvatures which is a unique characteristic of smectic LCs. This study can be regarded as a continuous effort in realizing the concept of green chemistry by using nontoxic and renewable feedstock in organic synthesis.

Research paper thumbnail of Dye Waste Treatment

Research paper thumbnail of Dye Waste Treatment

Dye wastes represent one of the most problematic groups of pollutants because they can be easily ... more 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. The co-removal of chromate Cr(VI) and azo dye Acid Orange 7 (AO7) using Brevibacterium casei under nutrient-limiting conditions has been studied [1]. AO7 was used as an electron donor by the reduction enzyme of Brevibacterium casei for the reduction of Cr(VI). The reduced chromate, Cr(III), complexed with the oxidized AO7 formed a purple intermediate. By using response surface OPEN ACCESS

Research paper thumbnail of Optimization of basic and reactive dye uptakes in binary dye solution using statistical experimental methodology

In the present study, the optimum adsorption conditions for the uptake of methylene blue (MB) and... more In the present study, the optimum adsorption conditions for the uptake of methylene blue (MB) and reactive orange 16 (RO16) in binary dye solution by ethylenediamine tetraacidic acid (EDTA) modified rice hulls was studied. By using the Plackett-Burman design, the significant variables in affecting the MB and RO16 uptake in binary dye solution were identified as pH and contact time. The combined effects of interaction between the variables were determined using response surface methodology (RSM). The model predicted that at optimum conditions: pH 6.77 and contact time of 205.58 min, the MB uptake greater than 95% could be obtained. As for RO16, the RSM indicated that pH 3.17 and contact time of 205.59 min were optimal for maximum percent dye uptake. These predicted values were also experimentally validated to confirm the reliability of the models.

Research paper thumbnail of Evaluation on the efficiency of ethylenediaminetetraacetic acid (EDTA)-modified rice husk as a low-cost sorbent for various dyes removal under continuous flow condition

The potential of ethylenediaminetetraacetic acid (EDTA)-modified rice husk (ERH) as a sorbent to ... more The potential of ethylenediaminetetraacetic acid (EDTA)-modified rice husk (ERH) as a sorbent to remove both methylene blue (MB) and reactive orange 16 (RO 16) in single and binary dye solutions was studied. Surface characterization of natural rice husk and ERH was investigated using field emission scanning electron microscope (FESEM) and atomic force microscope (AFM). From the FESEM micrographs, due to the absence of pores and cavities, it can be concluded that ERH is a non-porous material. The adsorption behaviour of MB and RO 16 onto column packed with ERH was investigated under continuous flow mode with three different parameters: the effect of influent concentration, the effect of bed depth and the effect of flow rate. Column studies indicated that the breakthrough time is longer for MB at lower influent concentration and flow rate. Unusual breakthrough curves were obtained for RO 16 in both single and binary dye solutions with very rapid initial breakthrough. This implies that the adsorption of RO 16 is a slow process and an effective adsorption only takes place after a sufficient lapse of time. Different mathematical models were used to characterize the fixed-bed performance for the adsorption process involved, namely bed depth service time (BDST) model, Adams-Bohart model and Clark model.

Research paper thumbnail of RJCE Single dye Lee WN

Research paper thumbnail of Application of response surface analysis for optimization of dyes sorption onto EDTA modified rice hull

The batch removal of basic and reactive dyes from aqueous solution using ethylenediamine tetraace... more The batch removal of basic and reactive dyes from aqueous solution using ethylenediamine tetraacetic acid modified rice husk (ERH) was studied. Plackett-Burman design coupled with response surface methodology (11SM) were adopted to evaluate the effect of various operating parameters, such aspH (2-10), contact time (5-420 mins) andsorbent dosage (0.05-0.2 g) on the percentage of dye removal. The optimum adsorption conditions for Methylene Blue were determined as pH: 8.6, contact time: 131 mins and sorbent dosage: 0.13 g. As for Reactive Orange 16, a greater uptake was observed at a lower pH. The empirical model developed from the interactive effects of important operating variables was validated using ANOVA analysis. The percentage uptakes predicted by the model are in good agreement with the experimental values, thus confirming the reliabilily of the models.

Research paper thumbnail of Synthesis and characterization of new Schiff base ester liquid crystals with fatty acids from palm oil as flexible alkyl chain

Industrial Crops and Products, 2021

Research paper thumbnail of Optimization of basic and reactive dye uptakes in binary dye solution using statistical experimental methodology

In the present study, the optimum adsorption conditions for the uptake of methylene blue (MB) and... more In the present study, the optimum adsorption conditions for the uptake of methylene blue (MB) and reactive orange 16 (RO16) in binary dye solution by ethylenediamine tetraacidic acid (EDTA) modified rice hulls was studied. By using the Plackett-Burman design, the significant variables in affecting the MB and RO16 uptake in binary dye solution were identified as pH and contact time. The combined effects of interaction between the variables were determined using response surface methodology (RSM). The model predicted that at optimum conditions: pH 6.77 and contact time of 205.58 min, the MB uptake greater than 95% could be obtained. As for RO16, the RSM indicated that pH 3.17 and contact time of 205.59 min were optimal for maximum percent dye uptake. These predicted values were also experimentally validated to confirm the reliability of the models.

Research paper thumbnail of Evaluation on the efficiency of ethylenediaminetetraacetic acid (EDTA)-modified rice husk as a low-cost sorbent for various dyes removal under continuous flow condition

Desalination and Water Treatment, 2015

AbstractThe potential of ethylenediaminetetraacetic acid (EDTA)-modified rice husk (ERH) as a sor... more AbstractThe potential of ethylenediaminetetraacetic acid (EDTA)-modified rice husk (ERH) as a sorbent to remove both methylene blue (MB) and reactive orange 16 (RO 16) in single and binary dye solutions was studied. Surface characterization of natural rice husk and ERH was investigated using field emission scanning electron microscope (FESEM) and atomic force microscope (AFM). From the FESEM micrographs, due to the absence of pores and cavities, it can be concluded that ERH is a non-porous material. The adsorption behaviour of MB and RO 16 onto column packed with ERH was investigated under continuous flow mode with three different parameters: the effect of influent concentration, the effect of bed depth and the effect of flow rate. Column studies indicated that the breakthrough time is longer for MB at lower influent concentration and flow rate. Unusual breakthrough curves were obtained for RO 16 in both single and binary dye solutions with very rapid initial breakthrough. This implies that the adsorption...

Research paper thumbnail of Dye Waste Treatment

Research paper thumbnail of Synthesis and characterization of new Schiff base ester liquid crystals with fatty acids from palm oil as flexible alkyl chain

Palm oil plays an important role in both food and non-food industries. With the aim of further di... more Palm oil plays an important role in both food and non-food industries. With the aim of further diversifying the non-food applications of palm oil, the viability of using palm fatty acids in the synthesis of liquid crystals (LCs) has been investigated. In this study, three types of palm fatty acid, namely lauric acid, palmitic acid and stearic acid were used as a source of flexible alkyl chain, which is an influential structural feature of LCs. This flexible alkyl chain is usually derived from non-renewable petrochemicals. Three palm-based LCs (PBLCs), namely, PB 1 (lauric-based LC), PB 2 (palmitic-based LC) and PB 3 (stearic-based LC) have been synthesized and the presence of liquid crystallinity was further verified by Polarizing Optical Microscopy (POM), Differential Scanning Calorimetry (DSC) and Wide Angle X-ray Diffraction (WAXD). Mesophase was observed from POM analysis for PB 1-PB 3 and based on the scattering pattern of WAXD at small angle region, the texture of the mesophase was Smectic A phase. The synthesized PBLCs can be potential candidate for various practical applications such as engineering of nanostructure and biomaterials due to the presence of curvatures which is a unique characteristic of smectic LCs. This study can be regarded as a continuous effort in realizing the concept of green chemistry by using nontoxic and renewable feedstock in organic synthesis.

Research paper thumbnail of Dye Waste Treatment

Research paper thumbnail of Dye Waste Treatment

Dye wastes represent one of the most problematic groups of pollutants because they can be easily ... more 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. The co-removal of chromate Cr(VI) and azo dye Acid Orange 7 (AO7) using Brevibacterium casei under nutrient-limiting conditions has been studied [1]. AO7 was used as an electron donor by the reduction enzyme of Brevibacterium casei for the reduction of Cr(VI). The reduced chromate, Cr(III), complexed with the oxidized AO7 formed a purple intermediate. By using response surface OPEN ACCESS

Research paper thumbnail of Optimization of basic and reactive dye uptakes in binary dye solution using statistical experimental methodology

In the present study, the optimum adsorption conditions for the uptake of methylene blue (MB) and... more In the present study, the optimum adsorption conditions for the uptake of methylene blue (MB) and reactive orange 16 (RO16) in binary dye solution by ethylenediamine tetraacidic acid (EDTA) modified rice hulls was studied. By using the Plackett-Burman design, the significant variables in affecting the MB and RO16 uptake in binary dye solution were identified as pH and contact time. The combined effects of interaction between the variables were determined using response surface methodology (RSM). The model predicted that at optimum conditions: pH 6.77 and contact time of 205.58 min, the MB uptake greater than 95% could be obtained. As for RO16, the RSM indicated that pH 3.17 and contact time of 205.59 min were optimal for maximum percent dye uptake. These predicted values were also experimentally validated to confirm the reliability of the models.

Research paper thumbnail of Evaluation on the efficiency of ethylenediaminetetraacetic acid (EDTA)-modified rice husk as a low-cost sorbent for various dyes removal under continuous flow condition

The potential of ethylenediaminetetraacetic acid (EDTA)-modified rice husk (ERH) as a sorbent to ... more The potential of ethylenediaminetetraacetic acid (EDTA)-modified rice husk (ERH) as a sorbent to remove both methylene blue (MB) and reactive orange 16 (RO 16) in single and binary dye solutions was studied. Surface characterization of natural rice husk and ERH was investigated using field emission scanning electron microscope (FESEM) and atomic force microscope (AFM). From the FESEM micrographs, due to the absence of pores and cavities, it can be concluded that ERH is a non-porous material. The adsorption behaviour of MB and RO 16 onto column packed with ERH was investigated under continuous flow mode with three different parameters: the effect of influent concentration, the effect of bed depth and the effect of flow rate. Column studies indicated that the breakthrough time is longer for MB at lower influent concentration and flow rate. Unusual breakthrough curves were obtained for RO 16 in both single and binary dye solutions with very rapid initial breakthrough. This implies that the adsorption of RO 16 is a slow process and an effective adsorption only takes place after a sufficient lapse of time. Different mathematical models were used to characterize the fixed-bed performance for the adsorption process involved, namely bed depth service time (BDST) model, Adams-Bohart model and Clark model.

Research paper thumbnail of RJCE Single dye Lee WN