Basic Dye Adsorption

The pitaya peel (Hylocereus undatus) was carbonized in the presence of ZnCl 2 to obtain a carbon-based adsorbent to remove the Metanil Yellow dye (MY) from colored waters. The characterization techniques confirmed that the material had morphological changes with the appearance of new irregularities and cavities. Besides, the alternative adsorbent was formed mainly by carbon and functional groups characteristic of lignin and cellulose. Isothermal and kinetic studies were carried out at the natural pH of the solution at a dosage of 0.4 g L -1 . The Langmuir model demonstrated the best adjustment of the equilibrium isotherms of the system, reaching the maximum adsorption capacity of 144.07 mg g -1 at 298 K. The thermodynamic behavior indicated that it is a spontaneous and favorable process of an exothermic nature (ΔH 0 =-34.02 kJ mol -1 ), consistent with a mechanism involving electrostatic interactions. The MY concentration influenced the kinetic. The homogeneous surface diffusion model (HSDM) showed good statistical adjustment to the kinetic values, showing a slight increase in the diffusivity coefficient from 2.4 × 10 -9 to 4.5 × 10 -9 cm 2 s -1 with the increased MY concentration. The material application in a mixture containing several dyes and salts in the circumstances close to the real ones showed removal of 82.5%. The adsorbent could be regenerated and used 12 times. Therefore, it can be concluded that the pitaya fruit residual biomass can be used as a precursor for preparing carbon-based adsorbents. The adsorbent, in turn, is a promising alternative in the treatment of MY dye and mixtures of organic molecules.

After thanking Allah, who granted me the ability to finish this work, I would like to express my sincere gratitude to my thesis supervisors: Prof. Hikmat Hilal for all his guidance, understanding, support and sound advice in all aspects of my research work and Prof. Amer El-Hamouz for his scientific support, encouragement, guidance and constructive advice. I would like to acknowledge the Palestinian Central Public Health Laboratory for their cooperation. In particular, I thank my friend Lama Awartani for offering help and making arrangements. I also thank Nour Halayqa and Ahed Halayqa for their assistance in nitrate concentration measurement. I would like to thank Dr. Dae Hoon Park (Dansuk Co., Seoul, S. Korea) and Dr. Guy Campet (ICMCB, University of Bordeaux, France) for performing SEM measurements. I thank Dr. Ahed Zyoud for his help in nitrite concentration measuring. Special thanks to Dr. Taha Kenjo who provided me with many published scientific papers about my work. I appreciate help and support from all members of the Chemistry Department at An-Najah National University especially laboratory technicians, in particular Mr. Nafiz Dweikat. My warm thanks to my dear friends, especially Fedaa Talal and Manar Ata Allah for all their support, motivation, and help. Parents, my sisters and brothers thank you for being a great source of support, love and encouragement which have always carried me through the way. Finally, my greatest gratitude to my husband Rami Nassar for his care and unreserved support which gave me the courage and confidence that I need in my life. Hiba v ‫ار‬ ‫اإلقر‬

The textile industry is using several thousands of quantities of dyes and chemicals in various processes of textile manufacture including dyeing and printing all of which require large quantities of water. Water consumption for dyeing varies from 30-50 L/kg of cloth depending on the type of dye used. An average sized textile mill has a production of about 8000 Kg of fabric per day. It may use as much as ca. 1.6 million liters of water 16 % of which may be consumed in dyeing and 8 % in printing. Dyeing section itself contributes to 15-20 % of the total waste water flow 1. Use of synthetic dyes has been seen to have a toxic nature and causes an adverse effect on all forms of life. Presence of sulphur, naphthol, vat dyes, nitrates, acetic acid, soaps, enzymes chromium compounds and heavy metals like copper, arsenic, lead, cadmium, mercury, nickel and cobalt and certain auxiliary chemicals all collectively make the textile effluent highly toxic. Other harmful chemicals present in the water may be formaldehyde based dye fixing agents, chlorinated stain removers, hydrocarbon based softeners, non biodegradable dyeing chemicals. These organic materials react with many disinfectants especially chlorine and form by products that are often carcinogenic and therefore undesirable. Many of these also show allergic reactions 2. The colloidal matter present along with colors and oily scum increases the turbidity, gives the water a bad appearance

Prosopis juliflora bark, an agricultural by product, acts as an effective adsorbent for the removal of dyes. In the present study, the effectiveness of Prosopis juliflora bark in absorbing Direct yellow 12 from aqueous solution has been studied as a function of agitation time, dye concentration, adsorbent dose, pH and temperature. The maximum adsorption of dye by Prosopis juliflora bark occurred at pH of 3. Characterization of adsorbent like proximate analysis, point zero charge and bulk density are evaluated with the standard methods. Experimental results indicated that more than 85% of removal of dye is possible with the use of this low cost adsorbent Prosopis juliflora bark. It is proposed that Prosopis juliflora bark is an agriculture waste, locally available, environmentally benign (green) at low cost is suitable for the removal of synthetic anionic dye from aqueous solution.

I appreciate help and support from all members of the Chemistry Department at An-Najah National University especially laboratory technicians, in particular Mr. Nafiz Dweikat. My warm thanks to my dear friends, especially Fedaa Talal and Manar Ata Allah for all their support, motivation, and help. Parents, my sisters and brothers thank you for being a great source of support, love and encouragement which have always carried me through the way. Finally, my greatest gratitude to my husband Rami Nassar for his care and unreserved support which gave me the courage and confidence that I need in my life. Hiba v ‫ار‬ ‫اإلقر‬

Prosopis juliflora bark, an agricultural by product, acts as an effective adsorbent for the removal of dyes. In the present study, the effectiveness of Prosopis juliflora bark in absorbing Direct yellow 12 from aqueous solution has been studied as a function of agitation time, dye concentration, adsorbent dose, pH and temperature. The maximum adsorption of dye by Prosopis juliflora bark occurred at pH of 3. Characterization of adsorbent like proximate analysis, point zero charge and bulk density are evaluated with the standard methods. Experimental results indicated that more than 85% of removal of dye is possible with the use of this low cost adsorbent Prosopis juliflora bark. It is proposed that Prosopis juliflora bark is an agriculture waste, locally available, environmentally benign (green) at low cost is suitable for the removal of synthetic anionic dye from aqueous solution.

The pitaya peel (Hylocereus undatus) was carbonized in the presence of ZnCl 2 to obtain a carbon-based adsorbent to remove the Metanil Yellow dye (MY) from colored waters. The characterization techniques confirmed that the material had morphological changes with the appearance of new irregularities and cavities. Besides, the alternative adsorbent was formed mainly by carbon and functional groups characteristic of lignin and cellulose. Isothermal and kinetic studies were carried out at the natural pH of the solution at a dosage of 0.4 g L − 1. The Langmuir model demonstrated the best adjustment of the equilibrium isotherms of the system, reaching the maximum adsorption capacity of 144.07 mg g − 1 at 298 K. The thermodynamic behavior indicated that it is a spontaneous and favorable process of an exothermic nature (ΔH 0 =− 34.02 kJ mol − 1), consistent with a mechanism involving electrostatic interactions. The MY concentration influenced the kinetic. The homogeneous surface diffusion model (HSDM) showed good statistical adjustment to the kinetic values, showing a slight increase in the diffusivity coefficient from 2.4 × 10 − 9 to 4.5 × 10 − 9 cm 2 s − 1 with the increased MY concentration. The material application in a mixture containing several dyes and salts in the circumstances close to the real ones showed removal of 82.5%. The adsorbent could be regenerated and used 12 times. Therefore, it can be concluded that the pitaya fruit residual biomass can be used as a precursor for preparing carbon-based adsorbents. The adsorbent, in turn, is a promising alternative in the treatment of MY dye and mixtures of organic molecules.

In this paper, an attempt has been made to produce activated carbon from tamarind wood, which is a forest waste, rich in lignocellulosic material. The characterisation of the activated carbon is done based on carbonisation time, temperature, pore volume and Brunauer, Emmett and Teller (BET) surface area under various operating conditions. The Scanning Electron Microscopy (SEM) analysis is also done to study the morphological changes of the chemically activated carbon. The best condition for the production of the high BET surface area of 1240 m 2 /g activated carbon from tamarind wood by chemical activation is found to be 100% chemical ratio (activated agent/precursor) at a carbonisation time of 60 min and carbonisation temperature of 500°C.

After thanking Allah, who granted me the ability to finish this work, I would like to express my sincere gratitude to my thesis supervisors: Prof. Hikmat Hilal for all his guidance, understanding, support and sound advice in all aspects of my research work and Prof. Amer El-Hamouz for his scientific support, encouragement, guidance and constructive advice. I would like to acknowledge the Palestinian Central Public Health Laboratory for their cooperation. In particular, I thank my friend Lama Awartani for offering help and making arrangements. I also thank Nour Halayqa and Ahed Halayqa for their assistance in nitrate concentration measurement. I would like to thank Dr. Dae Hoon Park (Dansuk Co., Seoul, S. Korea) and Dr. Guy Campet (ICMCB, University of Bordeaux, France) for performing SEM measurements. I thank Dr. Ahed Zyoud for his help in nitrite concentration measuring. Special thanks to Dr. Taha Kenjo who provided me with many published scientific papers about my work. I appreciate help and support from all members of the Chemistry Department at An-Najah National University especially laboratory technicians, in particular Mr. Nafiz Dweikat. My warm thanks to my dear friends, especially Fedaa Talal and Manar Ata Allah for all their support, motivation, and help. Parents, my sisters and brothers thank you for being a great source of support, love and encouragement which have always carried me through the way. Finally, my greatest gratitude to my husband Rami Nassar for his care and unreserved support which gave me the courage and confidence that I need in my life. Hiba v ‫ار‬ ‫اإلقر‬

This study aimed to investigate the removal of a reactive dye from aqueous solution by adsorption. Activated carbon prepared from olive stone, an agricultural solid by-product, was used as adsorbent. Different amounts of activating agent (ZnCl 2) and adsorbent particle size were studied to optimise adsorbent surface area. The adsorption experiments were conducted at different process parameters such as adsorbent dose, temperature, equilibrium time and pH. The experimental results showed that at equilibrium time 120 min, optimum pH ranged between 3 and 4, and adsorbent dosage was 2.0 g 200 ml)1. While the kinetic data support pseudo-second order, a pseudo-first order model shows very poor fit. Adsorption isotherms were obtained at three different temperatures (288, 298 and 308 K). The fitness of adsorption data to the Langmuir and Freundlich isotherms was investigated. In addition, the thermodynamic parameters such as isosteric enthalpy of adsorption (DH ads) y , isosteric entropy of adsorption (DS ads) y and free energy of adsorption DG 0 ads were calculated. BET surface area measurements were made to reveal the adsorptive characteristics of the produced active carbon. The surface area of the activated carbon produced with 20% w/w ZnCl 2 solution was 790.25 m 2 g)1 .

The adsorption of dyes from aqueous solutions using various adsorbents has proved to be a promising approach in wastewater treatment units. Recently a number of adsorbents have been tested for their utility for waste water treatment. This paper investigates the utility of Prosopis Juliflora Bark Powder (PJB), an agricultural waste available in large quantity in India, as low-cost adsorbent to remove basic dye (Basic violet 14, BV14). Batch mode experiments were conducted at 35žC to study the effects of adsorbent dosage, initial concentration of BV14, contact time and pH on dye adsorption. Physico-chemical characters of PJB were studied. The Point zero charge of Prosopis Juliflora Bark was estimated by pH drift method and surface functional groups by Fourier transform infrared (FTIR) spec-troscopy before and after adsorption. The experimental results indicate potential of PJB as an adsorbent for removal of Basic Violet or Basic Fuchsine as an adsor-bent for the removal of dyes from aqueous solutions This method is beneficial for the waste water treatment. It was estimated that eco friendly and cost effective materials can be prepared as adsorbents for the removal of dyes.

Prosopis juliflora bark, an agricultural by product, acts as an effective adsorbent for the removal of dyes. In the present study, the effectiveness of Prosopis juliflora bark in absorbing Direct yellow 12 from aqueous solution has been studied as a function of agitation time, dye concentration, adsorbent dose, pH and temperature. The maximum adsorption of dye by Prosopis juliflora bark occurred at pH of 3. Characterization of adsorbent like proximate analysis, point zero charge and bulk density are evaluated with the standard methods. Experimental results indicated that more than 85% of removal of dye is possible with the use of this low cost adsorbent Prosopis juliflora bark. It is proposed that Prosopis juliflora bark is an agriculture waste, locally available, environmentally benign (green) at low cost is suitable for the removal of synthetic anionic dye from aqueous solution.

Many human-made organic chemical compounds are currently possible to be detected in drinking water sources, hence, they are of increasing interest, because of their potential toxicity, carcinogenicity and mutagenicity effects. Among them, dyes from textile processing wastewater can enter in drinking water supplies. In this study, biologically treated textile wastewater, treated by activated carbon made from solved extracted olive pulp residue and olive wooden stone. Since these are waste materials, their use in the synthesis of activated carbon production process will reduce solid waste pollution. The results show that the COD of textile wastewater reduced for about 74%, as well as the TOC removal efficiency was 72%. Additional a maximum 84% remove of color was achieved by using 800 mg/L powder activated carbon dosage. These activated carbons were proved to be efficient adsorbents for the removal of water pollutants and contaminants

Removal of dye Eosin on two different samples of activated carbon by static batch method was studied. Experimental data on optical density of blank solutions of different concentrations ranging from 10 to 100 mg/L and optical density of solutions after adsorption on activated carbon samples were taken and analyzed. Calibration curves were plotted and the amount of dye adsorbed was calculated. The data was fitted to Langmuir and Freundlich isotherms for two different carbon samples and different concentration values. Constants were calculated from the slope and intercept values of the isotherms. Coefficient of correlation R 2 and Standard Deviation SD were also noted. The data fitted well to the isotherms. It was observed that adsorption decreased with increase in ppm concentrations. Carbon sample C 2 showed higher potential to adsorb the dye Eosin as compared to carbon sample C 1 . Further Carbon sample C 2 showed better adsorption in acidic pH as compared to in alkaline pH. From the analysis of the data it is shown that C 2 sample has a good capacity to remove the textile dye from the residue water.

In this study, the adsorption mechanism of cethyltrimethylammonium bromide (CTAB), a cationic surfactant, onto powdered active carbon (PAC) from aqueous solution was investigated and also some thermodynamic quantities such as isosteric adsorption enthalpy and entropy for this system were determined. In addition, the mechanistic and thermodynamic results of the experiments were supported with the surface zeta potential measurements. It was found that 5 min is sufficient in order to reach adsorption equilibrium. The adsorption of CTAB onto active carbon/water interface mainly takes place through ion exchange, the ion pairing and hydrophobic bonding. The predominant mechanisms in the lower CTAB concentrations are probably ion exchange and ion pairing. The hydrophobic bonding mechanism predominates with the increasing CTAB concentration. It was determined that the signs of isosteric adsorption enthalpy (DH~) and isosteric adsorption entropy (DS~) for adsorption of CTAB onto PAC are negative and positive, respectively. As temperature increases, the amount of CTAB adsorbed is decreased indicating the exothermic nature of adsorption process. This decreasing verifies the negative sign expected of (DH ads )~. As a result of the adsorption, since the number of the water molecules surrounding the hydrocarbon tails of CTAB molecules decreases and thus the degree of freedom of the water molecules increases, the positive sign of (DS ads )~points out the hydrophobic bonding mechanisms. D

This study aimed to investigate the removal of a reactive dye from aqueous solution by adsorption. Activated carbon prepared from olive stone, an agricultural solid by-product, was used as adsorbent. Different amounts of activating agent (ZnCl2) and adsorbent particle size were studied to optimise adsorbent surface area. The adsorption experiments were conducted at different process parameters such as adsorbent dose, temperature, equilibrium time and pH. The experimental results showed that at equilibrium time 120 min, optimum pH ranged between 3 and 4, and adsorbent dosage was 2.0 g 200 ml−1. While the kinetic data support pseudo-second order, a pseudo-first order model shows very poor fit. Adsorption isotherms were obtained at three different temperatures (288, 298 and 308 K). The fitness of adsorption data to the Langmuir and Freundlich isotherms was investigated. In addition, the thermodynamic parameters such as isosteric enthalpy of adsorption (ΔHads)y, isosteric entropy of adsorption (ΔSads)y and free energy of adsorption ΔG0ads were calculated. BET surface area measurements were made to reveal the adsorptive characteristics of the produced active carbon. The surface area of the activated carbon produced with 20% w/w ZnCl2 solution was 790.25 m2 g−1.

This study aimed to investigate the removal of a reactive dye from aqueous solution by adsorption. Activated carbon prepared from olive stone, an agricultural solid by-product, was used as adsorbent. Different amounts of activating agent (ZnCl 2 ) and adsorbent particle size were studied to optimise adsorbent surface area. The adsorption experiments were conducted at different process parameters such as adsorbent dose, temperature, equilibrium time and pH. The experimental results showed that at equilibrium time 120 min, optimum pH ranged between 3 and 4, and adsorbent dosage was 2.0 g 200 ml )1 . While the kinetic data support pseudo-second order, a pseudo-first order model shows very poor fit. Adsorption isotherms were obtained at three different temperatures (288, 298 and 308 K). The fitness of adsorption data to the Langmuir and Freundlich isotherms was investigated. In addition, the thermodynamic parameters such as isosteric enthalpy of adsorption (DH ads ) y , isosteric entropy of adsorption (DS ads ) y and free energy of adsorption DG 0 ads were calculated. BET surface area measurements were made to reveal the adsorptive characteristics of the produced active carbon. The surface area of the activated carbon produced with 20% w/w ZnCl 2 solution was 790.25 m 2 g )1 .