ADSORPTION OF Cu (II) AND Ni (II) FROM AQUEOUS SOLUTION BY CANISTEL (Pouteria campechiana): EQUILIBRIUM, KINETICS AND THERMODYNAMICS STUDIESA Thesis Proposal

Presented to the

Faculty of the College of Science

Pamantasan ng Lungsod ng Maynila

In partial fulfilment

of the requirement for the degree

Bachelor of Science in Chemistry

By:

Jesamyn L. Camagong

CONTENTS

INTRODUCTION

1

1.1 Objectives of the Study

21.2 Scope and Limitations

3RELATED LITERATURE

42.1 Canistel

2.2 Metal Ions 2.2.1 Toxicity of Copper (II)

2.2.2 Toxicity of Nickel (II)

2.3 Common Waste Water Treatment

2.3.1 Chemical Precipitation

2.3.2 Ultrafiltration

2.3.3 Ion Exchange

2.3.4 Reverse Osmosis

2.4 Adsorption: Alternative Method

2.5 Adsorption Process

2.5.1 Physical

2.5.2 Chemical2.6 Adsorption Isotherm

2.6.1 Langmuir Isotherm

2.6.2 Freundlich Isotherm

2.6.3 Temkin Isotherm

2.6.4 Dubinin-Radushkevich Isotherm

2.6.5 Redlich-Peterson

2.7 Adsorption Kinetics

2.7.1 Pseudo-first order model

2.7.2 Pseudo-second order model

2.7.3 Interparticle Diffusion

2.8 Adsorption Thermodynamics

2.9 Adsorbent Derived from Different MaterialsMETHODOLOGY

19

3.1 Materials (Reagents or Samples)

3.2 Preparation of the Canistel as an Adsorbent3.3 Base Treatment3.4 Characterization

3.4.1 FT-IR

3.4.2 SEM

3.4.3 BET

3.5 Preparation of Metal Ions

3.6Adsorptio Equilibrium

3.7 Adsorption Kinetics

3.8 Adsorption Thermodynamics

3.9 Statistical Analysis

BUDGET PROPOSAL

GANTT CHART

CHAPTER 1

INTRODUCTION

Heavy metal pollution is one of the major problems worldwide. Water pollution as one of these issues attracted a lot of concerns to people. The cause of this problem is due to the expansion of industrial activities [1]. The presence of heavy metals in the environment is a potential problem to the quality of the water because of its high toxicity.

Copper which is naturally present in the environment can be harmful to human when exposure is more than 15ppm. Acute copper poisoning intake can cause nausea, vomiting, diarrheal and there are some cases studied that if not cured can cause death [5]. The presence of copper in the water system was because of its improper disposal and copper mining [6]. Consequently, in order to avoid water pollution, treatment is needed before disposal [1].

Nickel is an element that occurs naturally but skin exposure of greater than 1-5ppm can cause skin allergy and irritation. On the other exposure to high level of nickel may results cancers of the lung [7]. Wearing jewelleries containing nickel is the most common reason an individual is exposed to nickel. Avoidance from wearing jewelleries containing nickel may limit the exposure.

Several treatment have been developed for removing copper and nickel from water such as chemical precipitation, ultra filtration, adsorption, ion exchange [4], reverse osmosis, oxidation, reduction[6] and electrolysis. Chemical precipitation used expensive sulfidic precipitant and it is not possible to do electro winning from precipitate. In addition, ultrafiltration cannot remove dissolved substances unless they are first adsorbed (with activated carbon). Furthermore, reverse osmosis requires a consumption of high specific energy and also electro winning of copper may not be possible because of the chloride in the concentrate.

Adsorption among all the method is highly effective and economical [4]. It is the cheapest method because the materials used are low cost. For most of the studies conducted low cost material has been a parameter in choosing the adsorbent material. This introduced the usage of agricultural waste for treating water system. Several by products are already used as a metal adsorbent but canistel peel has not reported.

In this study canistel peel will be use as the adsorbent. Canistel (pouteria campechiana) fruit is a round or ovoid, smooth and glossy. The peel and flesh of this fruit is yellow. Since highly cost commercial adsorbent materials are not practical to use so, this work will use an agricultural waste like canistel peel to remove heavy metal like copper in the water system.1.1 Objectives of the StudyThe following were the objectives of this research:

I. To characterize the unmodified and modified canistel powder.

II. to produced an adsorbent from the canistel peelIII. to modify canistel peel powder by base treatmentIV. to remove Cu (II) and Ni (II) from the wastewater using the canistel peel powderV. to determine the adsorption equilibrium, kinetics and thermodynamic parameters1.2 Scope and Limitations

In this study, the base modified canistel (Pouteria campechiana) peel will be use as an adsorbent for the removal of copper and nickel in artificial wastewater. Different isotherm models will be involved to describe adsorption process such as Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, and Redlich-Petrson. The following kinetic models will also be used such as Pseudo-first order model, Pseudo-second order model and Interparticle Diffusion. Thermodynamic parameters including H, G and S will also be determined.

This study will only be concern in the initial measurement of the parameters to be use such as the pH but the pH during and after the experiment cannot be regulated. The analytical concentration shall be treated as a whole.

CHAPTER II

RELATED LITERATURE

2.1 Canistel

Egg fruit or commonly known as Canistel (Pouteria campechiana) is a tropical fruit belonging to the family of Sapotaceae. Canistel trees can reach the height of 25m and have a trunk diameter up to 1.5m. Leaves are green and glossy and are held together at the end of the branches. Fruits are usually round or ovoid, smooth and glossy. Canistel is pale orange-yellow in color when fully ripe [2]. The plant of canistel is believed to b native of Southern Mexico and most countries of Central America. The tree was introduced to the Philippines by the Spaniards.

2.1 Metal Ion

2.2.1 Toxicity Copper

Copper is a mineral that occurs naturally in soil. It is an essential nutrient for humans and plants. Too little is unhealthy and too much can lead to copper poisoning. Copper (Cu) [21] is a reddish brown metal that is high ductility and malleability. It is a metal with very high thermal and electrical conductivity. Pure copper is soft and malleable. Copper (II) ions are water soluble

Copper imbalance can result from: environmental copper exposure, zinc deficiency and the copper personality. Copper poisoning can be triggered by stressed, excessive copper stored in live (>15ppm) and destruction of red blood cell.

Copper [42] strongly complexes to sludge, and it occurs mainly in the organic phase. Only a small fraction of the copper will be found in the solution as ionic copper (Cu2+). All heavy metals have its specific pH, for copper it is 5.5.

2.2.2 Toxicity of Nickel

Nickel [41] is a very hard metal that occurs naturally in soils and volcanic dust. Nickel is released to the atmosphere by windblown dust, volcanoes, combustion of fuel oil, municipal incineration, and industries involved in nickel refining, steel production, and other nickel alloy production. The form of nickel emitted to the atmosphere is dependent upon the source.

Nickel salts of strong acids and organic acids are soluble in water, whereas salts of weak inorganic acids are insoluble. Nickel is resistant to corrosion by air and water.The general population can be exposed to nickel via inhalation. Too much exposure to nickel can cause an allergic contact dermatitis; the primary targets of toxicity appear to be the respiratory tract following inhalation exposure.

2.3 Common Waste Water TreatmentChemical precipitation is an effective treatment for removing contaminants in water. The substance removability from water depends on the solubility of the various complexes formed in water [9]. Chemicals are added to form particles which settle and remove contaminants. The treated water is properly disposed or reused. It can also be used in a small or large scale.Ultrafiltration is a very competitive treatment compare to the conventional once. Ultrafiltration is necessary in producing safe water as far as disease is concerned. Today, more than 2 millions3/d of drinking water is produced worldwide through ultrafiltration. More than 50 UF plants for producing drinking water from surface water are in operation in the world.

Application of UF for drinking water supply can be in form of single operation without any pre-treatment except a common screen filter. UF can be used on its own for treating drinking water where the feed water is not too high in terms of organic content.

Ion exchange is the process at which ion are transferred to a solid matrix. In other words ions that are originally present in the solid were replaced by different ions. It requires interchange in the material because the electro neutrality of the solution must be maintained. It is physical separation process since atom is reversely removed from the waste water. It involves the regeneration of the ion exchanger by contacting the spent exchanger with a concentrated solution of an ion which can replace the ions adsorbed on the exchanger during the treatment process. Ion exchange is advantageous because is capable of handling and separating components from dilute waste water and it is possible to recycle components present in the waste and/or regenerating chemicals.Reverse Osmosis (RO) is a membrane process of purification which removes most of the total dissolved solids (TDS) in water. RO has become an important process for a wide variety of applications including: medical, laboratory, desalination, industrial wastewater and drinking water. Electrical conductivity is the most convenient method for testing RO water quality. In the process of reverse osmosis, water is produced through forcing it to semi permeable membranes at high pressure. The pH is also very useful in predicting membrane life and the scaling potential of feed water. The higher the pH and calcium, the more likely it is that scale will form on the membranes.

2.4 Adsorption: Alternative Method

Adsorption [32] is operative in most natural physical, biological, and chemical systems, and is widely used in industrial applications such as activated charcoal, synthetic resins and water purification. It is a process that occur when a gas or liquid solute accumulates on the surface of a solid or a liquid forming a molecular or atomic film. Adsorbate or solute is the material being adsorbed while adsorbent is the solid material being used as the adsorbing phase. The driving force for adsorption is the reduction in interfacial (surface) tension between the fluid and the solid adsorbent because of the adsorption of the adsorbate on the surface of the solid.

Many industrial wastewaters contain substances that are difficult to remove, toxic or hazardous, volatile and cannot be transferred to the atmosphere, present is very small concentrations that make and their removal via other methods difficult. Adsorption is advisable to use typically used because it can remove toxic or recalcitrant organic pollutants (especially halogenated but also no n-halogenated), and to a lesser extent, inorganic contaminants, from the wastewater. Adsorption also finds applications in tertiary wastewater treatment as a polishing step before final discharge. It is commonly used in the treatment of industrial wastewaters containing organic compounds not easily biodegraded during secondary (biological) treatment or toxic.

2.5 Adsorption Isotherm

2.5.1 Langmuir Isotherm

Langmuir isotherm model is valid for adsorption onto a surface with a finite number of identical sides. The binding sites have the same affinity for adsorption of single molecular layer. There is no interaction between the adsorbed molecules.

It is an empirical isotherm derived from a proposed kinetic mechanism. For liquids (adsorbate) adsorbed on solids (adsorbent), the Langmuir can be expressed by: (1)where qeq is the adsorbate loading (mg g1) at equilibrium, Ceq the equilibrium concentration in the fluid (mg l1), qmax the adsorption capacity (mg g1) and Ka sorption equilibrium constant (l mg1) [12].

Table 1.1.Capacities for Cu (II) of various adsorbents

Material Used Modifying agentQmax (mg.g-1)Reference

Streptomyces coelicolorA3(2) 66.66 [22]

Dehydrated Wheat Bran 42.4 [23]

Algae Gracilaria 2.527 [24]

Modified orange peel Methyl acrylate 289.0 [20]

Capsicum annuum seeds 4.47 x 10-4 [25]

Meranti Sawdust 32.051 [21]

Palm Kernel Fibre 3.169 x 10 -4

[26]

Table 1.2.Capacities for Ni (II) of various adsorbents

Material UsedModifying agentQmax (mg.g-1)Reference

Granulated Activated Carbon1.2827[28]

Helix Aspera Shells0.2273[38]

Streptomyces coelicolorA3(2)416.6[22]

Sugarcane Bagasse2.80[25]

Meranti sawdust35.971[21]

Bakers YeastHCl, Bromine9.01[36]

2.5.2 Freundlich IsothermIn 1907, Freundlich isotherm is obtained on the assumption that the sorption takes place on the heterogeneous surface. The sorption energy decrease exponentially.

A linear form of the Freundlich equation is:

(2)

where K and n are Freundlich adsorption isotherm constants (dm3 g1), the plot of ln qe versus lnCe for the adsorption was employed [13].Table 2.1 Freundlich constants for Cu (II) of various adsorbents

Material Used 1/nKf Reference

(mg.g-1)

Ulvafasciatasp. 2.2163 2.2230 [39]

Treated oil shale ash 4.237 1.325 [40]

Dehydrated wheat bran 0.1408 26.2 [23]

Algae Gracilaria 0.3798 0.640 [24]

Modified Orange peel 18.93 0.504 [20]

Capsicum annuumseeds 7.16x10-3 0.4593 [25]

Meranti Sawdust 1.460 0.9900 [21]

Palm Kernel Fibre 3.488 7.03 x 10-4 [26]

Table 2.2.Freundlich constants for Ni (II) of various adsorbents

Material Used1/n KfReference

(mg.g-1)

Helix Aspera Shells0.8330.2273 [33]

SpagnumPeat0.10359.06 [21]

Streptomyces coelicolorA3(2)0.980.08 [22]

Natural iron-oxide coated sand0.980.99 [29]

Meranti Sawdust1.4830.99 [21]

Bakers Yeast0.17003.73 [36]

2.5.3 Temkin Isotherm

The Temkin Isotherm assumes that the sorption is linear not logarithmic as implied in the Freundlich isotherm. It is expressed as

(3)

where, q is the amount of metal ions adsorbed at equilibrium (mg.g-1), Ce is the equilibrium concentration (mg.L-1), A and b are the Temkin constants, R is the universal gas constant, and T is the temperature of the system [14].2.5.4 Dubinin-Radushkevich IsothermIt is insufficient to explain the physical and chemical characteristic of adsorption using the Freundlich and Langmuir Isotherm. D-R Isotherm is commonly used to describe the sorption isotherm of the single solute systems. It is more general since it rejects the homogeneous surface [11]. The D-S is expressed as

(4)where qe, the amount of adsorbed per unit weight (mg/g); K, Freundlich constants related to adsorption capacity; Ce, the equilibrium concentration (mg/L); n, Freundlich constants related to adsorption intensity.

2.5.5 Redlich-Peterson

In describing the empirical isotherm for redlich-peterson, three parameters are used, [KR], [aR], and [. The mechanism of adsorption is hybrid [15].

(7)2.6 Adsorption Kinetics2.6.1 Pseudo-first order modelThe pseudo-first rate order is expressed as follows:

(8)

where q1 and qt are the amounts of the substance ions adsorbed at equilibrium and at time t (mg g1) and k1 is the pseudo-first-order rate constant (min1) of adsorption. Values of k1 can be calculated from the slope of the plots of 1/qt versus 1/t [16]. 2.6.2 Pseudo-second order modelPseudo-second order rate model was described in the literature in the following form:

(9)

where, h is the initial sorption rate (mg g-1 min-1); k2 is the overall rate constant for the sorption process (g mg-1 min-1); qe (2) is the amount of metal ion adsorbed at equilibrium (mg/g); and qt is the adsorbed at time t (mg/g) [16].

Table 3.1.Mechanisms of adsorption for Cu (II) and Ni (II)Material UsedsoluteModel Reference

AlgaUndariapinnatifida Cu (II)2nd order[30]

AlgaUndariapinnatifida Ni (II)2nd order[30]

Algae Gracilaria Cu (II)2nd order[31]

Modified Orange peel Cu (II)2nd order[20]

Capsicum annuumseeds Cu (II)2nd order[32]

Maize Cob Cu(II)2nd order[34]

Cassava Waste Cu (II)2nd order[33]

Meranti Sawdust Cu (II)1st, 2nd order[21]

Meranti Sawdust Ni (II)1st, 2nd order[21]

Fired Coal Fly Ash Cu (II)2nd order[35]

Bakers Yeast Ni (II)2nd order[36]

Zeolite X Ni (II)2nd order[37]

2.6.3 Interparticle Diffusion

The intraparticle diffusion equation can be written as follows:

(10)

where C is the intercept and kp, the intraparticle diffusion rate constant (mg g1 min1/2) [16].

2.7 Adsorption Thermodynamics

Adsorption thermodynamic parameters are useful in determining whether the reaction is endothermic or exothermic and the spontaneity of adsorption [17]. Thermodynamic parameters such as change in enthalpy (H), free energy change (G) and entropy change (S) can be estimated using equilibrium constant with changing temperature. The free energy reaction is given by the following equation:

G = -RT ln Ka

(11)

where _G is standard free energy change, J; R the universal gas constant, 8.314 J mol1 K1 and T the absolute temperature, K.

Free energy change indicates that the higher the negative value reflects a more energetically favorable adsorption and the degree of spontaneity of the adsorption process [18].

The plot of ln KL as a function of 1/T yields a straight line from which (H) and (S) can be calculated from the slope and intercept, respectively [19].

(12)

Table 4.1.Thermodynamic value for Cu (II) and Ni (II) of various adsorbents

________________________________________________________________

Material Used G (kJ/mole) H

(kJ/mole) S (kJ/moleK)Reference

________________________________________________________________

Andesite Products16.5024.040661.69 [27]

Natural iron-oxide coated sand20.9152.320.25 [29]

Palm Kernel Fibre-8.575.36770.0463 [26]

Helix aspera shell-1318.7 [38]

Natural iron-oxide coated sand-24.445.750.23 [29]

Bakers Yeast23.51930.70223.658 [36]

CHAPTER IIIMETHODOLOGY

3.1 Materials

The canistel peel that will be used in this study will be collected from the local market. The concentrations of (NO3)3.9H2O and Ni (NO3)2.6H2O which are of analytical grade will be used to prepare the metal ions Cu (II) and NI (II). For the base treatment, NaOH will be used.The instrument that will be used for drying the canistel peel is the 500 watts halogen lamp. The samples will be tested using AAS, FT-IR and SEM services.3.2 Preparation of Canistel Peel Adsorbent

Canistel peel will be used as the original material for the preparation of adsorbent. The canistel peel will be collected from the local market. Clean the canistel peel with distilled water; chop in small pieces and dry using 500 watts halogen lamp. Grind the dried peel. The ground peel will be sieved to make the size of the particles 80m. After sieving, boil it for 15 minutes to remove the colour. To modify the substrate, treat 5g of canistel peel with 25ml of 0.1M NaOH and for the remaining potion, used it as the unmodified. Neutralize the treated substrate by washing it with distilled water. As the pH neutralizes dry again the substrate. Do constant weighing of the substrate.3.3 Base Treatment

The ground samples will be mixed with 0, 0.10, 0.25, and 0.50mol/L NaOH, and then will be stirred at 400 r/min for 30 min. Treatment of the sample with 0.50 mol/L NaOH for 60 and 120 min will also conducted for determining the optimum treatment time. After each base treatment, the samples will be filtered, wash extensively with distilled water until the final pH of the washing reached neutral. The sample will be dried in oven at 80C. The treated samples will be sieved.3.4 Characterization of Unmodified and Modified Adsorbent

The pH will be determined by adding 1 g of canistel peel powder in 50mL distilled water, stirred and the final pH will be measured after 24 hours. In addition, the Fourier transform infrared (FTIR) instrument will be used in the analysis. . Spectra of the samples will be collected by KBr disk method by blending 100mg adsorbent and KBr will be triturated with mortar and pestle for 10 minutes.

The BET specific surface areas were determined by standard multipoint techniques of nitrogen adsorption using a Micromeritics Gemini 2360 instrument. The untreated and modified canistel peel powder will be heated at 60 C for 2h before specific surface areas were measured.

The scanning electron micrograph (SEM) of the canistel peel powder and metal ions loaded canistel peel powder at bar length equivalent to 20_m, working voltage 15 kV with 250 magnification

3.5 Preparation of Metal IonsAll chemicals that will be used are of analytical grade. The stock solution of Copper and Nickel ions will be prepared from in1.0g L-1 concentration using Cu (NO3)3.9H2O and Ni (NO3)2.6H2O.

3.6 Adsorption Equilibrium

Adsorption equilibrium experiment will be carried out by contacting 0.2 g of powdered canistel peel with 100 ml of metal ion solution of different initial concentrations ranging from 60 to 140 mg/dm3. A series of such conical flasks will be maintained at 299 K. Equilibrium concentrations of Cu (II) and Ni (II) will be determined by Atomic Absorption Spectrophotometer.

3.7 Adsorption Kinetics

The studies of the kinetics of adsorption will be carried out at 30 C. One hundred ml of the solution containing the desired quantity of the metal ion will be treated with 0.5 g of canistel peel in stoppard conical flasks for the different times using a temperature-controlled stirrer. The solution will be filtered out and will be analyzed for its metal ion concentrations using Atomic Absorption Spectrometer, AAS.3.8 Adsorption Thermodynamics

One-hundred milligram sample of the powdered canistel peel will be added into a 100-mL solution of the Cu (II) and Ni (II) separately at initial concentration of 50ppm. Different samples will be soaked to water and let it to stand with a temperature of 303 K, 333 K and 363 K for 6 hours for three trials. The solution will be filtered out and will be analyzed for its metal ion concentrations using Atomic Absorption Spectrometer, AAS.

3.9 Statistical Analysis

The Pearson r is the measure of the strength of linear dependence between two variables X and Y. Paired T-test will be used to determine any significant difference in terms of adsorptive capacities of modified and non-modified adsorbents for Ni (II) and Cu (II).BUDGET PROPOSAL

ITEM/SERVICEUNIT COSTNO. OF UNITS NEEDEDTOTAL COSTSUPPLIER/

INSTITUTION

Canistel49/

1000 g4000 g196.00Super Market

100-ml peanut butter plastic containers2.80/ pc500pcs840.00Divisoria Market

Halogen lamp250/pc1pc250.00Handyman Hardware

Distilled water70/10L100L700.00SM Supermarket

Metal ions (Cu(II) and Ni(II))Cu(II)40/g

Ni(II)40/g 6g

6g

240.00

240.00

Lithium Lab Supplies

Sodium hydroxide, Concentrated3.00/

Ml100ml300.00Lithium Lab Supplies

KBr500.00Lithium Lab Supplies

Zip lock bags53.00/pack3 packs159.00Adams

Whatmann Filter paper No. 412.50/pc100pcs250.00Lithium Lab Supplies

AAS services700.00DLSU-Manila

FT-IR Services300/sample900.00DLSU-Manila

SEM Services1,000/sample3,000.00DLSU-Manila

Printing and bookbinding2,250.00Manila

TOTAL10,285.00

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