Yamin Yasin

Removal of lead ions from aqueous solutions using intercalated tartrate-Mg–Al layered double hydroxides

AbstractThe potential feasibility of layered double hydroxides (LDH) intercalated with tartrate (tartrate-Mg–Al) for the removal of lead ions from aqueous solutions was investigated. The effects of various experimental parameters such as contact time, solution pH, and adsorbent dosage were also investigated. The extent of lead ions removal increased with the increase in contact time and amount of tartrate-Mg–Al used; however, the percentage removal decreased with the increase in pH. The shape of the isotherms that was obtained from the experimental data was well fitted to the Langmuir isotherm. The fundamentals of lead removal from aqueous solution with the use of tartrate-Mg–Al could be explained by the formation of complexes between the tartrate and Pb2+ ions and for Mg–Al–NO3 it was the primary surface opposite charge precipitation reaction. The results from this study indicated that the LDH which intercalated with tartrate could be used as a potential adsorbent for the removal of lead ions from aqueou...

The Application of Response Surface Methodology for Lead Ion Removal from Aqueous Solution Using Intercalated Tartrate-Mg-Al Layered Double Hydroxides

Layered double hydroxide intercalated with tartrate (tartrate-Mg-Al) was used as an adsorbent to remove lead ions from aqueous solutions. The effects of various optimization parameters such as contact time, solution pH, lead ion concentrations, and adsorbent dosage were investigated by the use of Response Surface Methodology (RSM). The Response Surface Methodology (RSM) based on a four-level four-variable Central Composite Rotatable Design (CCRD) was employed to evaluate the interactive effects of the various optimization parameters. The parameters were contact time (6–10 h), solution pH (1–3), adsorbent dosage (0.06–0.1 g), and lead ion concentrations (10–30 mg/L). The percentage of lead ions removal for each of the parameters studied was determined by Inductively Coupled Plasma-Optical Emission Spectrophotometer. Simultaneously by increasing contact time and amount of dosage of tartrate-Mg-Al used the percentage of lead ions removal from aqueous solution will increase; however, the percentage removal decreases with an increase in pH and concentrations of lead ions. The experimental percentage removal recorded under optimum conditions was compared well with the maximum predicted value from the RSM, which suggest that Central Composite Rotatable Design of RSM can be used to study the removal of lead from aqueous solution by the use of tartrate-Mg-Al as an adsorbent.

Removal of Amido Black Dye from Aqueous Solution by Uncalcined and Calcined Hydrotalcite

Adsorption of amido black by calcined and uncalcined hydrotalcite was investigated. The influence of contact time, pH of the dye solution and adsorbent dose has been studied. In the light of so called “memory effect,” the removal of amido black, an anionic dye from aqueous solution by calcined hydrotalcite was also investigated. The results of adsorption experiments indicate that the percentage removal of amido black increased with increased in contact time and adsorbent dose but decreased with the increased in pH of the solution. Calcined hydrotalcite showed better adsorption capacity compared with uncalcined hydrotalcite. The isotherms showed that the adsorption of amido black was well fitted with Langmuir equation. The present study showed that hydrotalcite can be used as an adsorbent for the removal of amido black from aqueous solution. Better percentage removal of amido black performed by calcined hydrotalcite is due to their reconstruction of original layer in aqueous solution with good ion exchangers.

Application of response surface methodology in enzymatic synthesis: A review

There are very chemical reactions with very slow rates which can be catalyzed by enzymes. These biocatalysts need to moderate conditions for their catalytic activity and are stable in low temperature (between 15–50°C), average pH (5–10) and aqueous media. One of important things in enzymatic synthesis which has been recently noticed is the yield of reactions. Nowadays wide application of response surface methodology (RSM) was observed in organic chemistry. In one-variable-at-a-time technique only one parameter is changed and other parameters are kept at a constant level. It does not study the interactive effects among the variables, and does not illustrate the complete effects of the parameters on the process. Increasing the yield of product without increase in casts is carried out by modeling and optimization of reaction variables through statistical techniques such as RSM. In this paper, we reviewed some articles that used the RSM for optimization in the enzymatic synthesis.

Application of Response Surface Methodology for Optimization of Copper Removal from Aqueous Solution Using Magnesium Aluminium Hydrogenphosphate Layered Double Hydroxides

Magnesium-aluminium hydrogenphosphate layered double hydroxide that synthesized by used of co-precipitation and followed by hydrothermal (MAHP4) method was used as an adsorbent to remove copper ions from aqueous solutions. The effects of various optimization parameters such as contact time, adsorbent dosage and lead ion concentrations were investigated by used of Response surface methodology (RSM). The Response surface methodology (RSM) based on a four-level-three variables Central Composite Rotatable Design (CCRD) was employed to evaluate the interactive effects of the various optimization parameters. The parameters were contact time (2-6 h), adsorbent dosage (0.01 0.05 g) and copper ion concentrations (50 100 mg/l). Simultaneously by increasing contact time and amount of dosage of MAHP4 used, the percentage of lead ion removal from aqueous solution was increased. However, the percentage removal decreases with an increase in concentrations of copper ion. The experimental percentage removal recorded under optimum conditions was compared well with the maximum predicted value from the RSM which suggest that fractional factorial design of RSM can be used to study the removal of copper from aqueous solution by used of magnesium-aluminium hydrogenphosphate layered double hydroxide as an adsorbent.

Optimization of lead removal from aqueous solution using intercalated malate Mg-Al layered double hydroxides

Conventional optimization method was conducted for the removal of lead from aqueous solution by used of intercalated malate layered double hydroxides. The effects of various parameters such as contact time, amount of adsorbent dosage and the pH of the lead solution are studied. The extent of lead ions removal increased with the increased in contact time and amount of malate-Mg-Al used however, the percentage removal was decreased with the increased in concentration and pH. The fundamentals of lead removal from aqueous solution by used of malate-Mg-Al can be explained by the formation of complexes between the malate and Pb2+ ions. The results from this study indicated that layered double hydroxide intercalated with malate could be used as potential adsorbent for the removal of lead ions from aqueous solution.

Competitive adsorption of reactive dyes from binary mixture by MgAlNO 3 - layered double hydroxide

Adsorption of Reactive Black 5 (RB5) and Reactive Orange 16 (RO16) from their binary mixture using MgA-NO3 -layered double hydroxide (MgAlNO3-LDH) was conducted in a batch system. First order derivative spectrophotometric method was used for simultaneous analysis of RB5 and RO16 in binary mixtures. The effect of pH, contact time, and initial concentration were investigated. The results of these analyses showed that adsorption of reactive dyes were optimum at pH 2. Experimental data indicated that between the two reactive dyes in the mixture, RB5 was competitively better adsorbed than RO16 by LDH. Kinetic studies indicated that both pseudo first order and second order kinetic models fitted the experimental data with correlation R2> 0.96.

Adsorption of Reactive Orange 16 from aqueous solutions by MgAlNO 3 -LDH: Kinetic and equilibrium studies

An anionic MgAlNO3 layered double hydroxides (MgAlNO3-LDH) with Mg/Al molar ratio 4∶1, was investigated for its ability to adsorb an anionic dye, Reactive Orange 16 (RO16), with the objective of evaluating its suitability as an adsorbent. The experimental data were analyzed by the Langmuir and Freundlich adsorption models. Equilibrium data fitted well with Langmuir model for the concentration range of 5–100 mg/L. The equilibrium adsorption capacity of MgAlNO3-LDH was determined with the Langmuir equation and found to be 111 mg dye per gram adsorbent at 25 °C. Adsorption kinetics showed that the rates of adsorption were found to conform to the pseudo-second-order rather than first order kinetics. The results also indicate that MgAlNO3-LDH was a promising adsorbent for reactive dye removal from effluents, and with the potential to be used as an alternative adsorbent to other costly materials such as activated carbon.