2070100181610International Maritime College Oman
00International Maritime College Oman
The Research Council
FURAP – TRC Research Proposal
KHADIJA MURSHID ABDULLAH AL BALUSHI (03390-15)
AMIR GULL MOHAMED SHIRAN AL BALUSHI (03153-14)
SHEIKHA AHMED SULAIMAN ALI AL BALUSHI (02934-14)
SAID RASHID HUMAID AL QURRI (03234-14)
Dr. Meisam Valizadeh KiamahallehCo-Supervisor
Dr. Amin FirouziDepartment of Process Engineering
International Maritime College Oman
Falaj Al Qabail, Sohar (next to Sohar Industrial Port)
PO Box 532, PC 322 Falaj Al Qabail, Sohar, Sultanate of Oman
Tel: +968 26827748
Mobile: +968 71505932
E-mail: [email protected]
Development of carbon based material-Omani bio waste composite material for wastewater treatment
Waste streams coming from industries which reach water resources and soil have been identified to contain various contaminants such as heavy metal ions, bacterial contaminations, viruses, hazardous organic compounds, etc. This phenomenon is potentially hazard to human and the environment, Oman has been experiencing a massive load of marine wastes containing heavy metals with severe environmental and human health impacts. Adsorption techniques are being widely used by various researchers for the removal of various pollutants e.g. heavy metals and organic compounds from waste streams due to its sufficient removal, low cost and free complexity steps. In this work (CNTs) with bio-waste composite material will be used for the removal of wastewater contaminants.
CNTs have great potential as novel type of adsorbent due to their unique properties like high surface area, flexibility in the number of activated functional groups for enhancing the removal efficiency of contaminants, but it is difficult to use it in large scale applications due to its high cost. In recent years, the need for safe and economical methods for the elimination of various pollutants from contaminated water has necessitated research interest toward the production of low cost alternatives like bio-waste composite materials, this project aims to produce a low cost alternatives adsorbent from bio-waste composite materials and their feasibility for the removal of wastewater contaminants will be studied in detail with ultimate goal of reducing their environmental impacts.
Due to increasing awareness about the environment and stringent environmental regulations, wastewater treatment has always been a key aspect of research. Water is a vital component for the economic prosperity of any country. In coming years, the economic importance of water is expected to grow with the global economic growth, Nowadays clean and safe water accessibility is shrinking, water resources are polluted by various sources and removal of water pollutants is one of the biggest challenges in ensuring safe and clean water as well as protecting the environment. Oman has been experiencing a massive load of marine wastes containing heavy metals with severe environmental and human health .Industrial wastewater contains the variety of organic and inorganic compounds which are characterized as toxic, carcinogenic and mutagenic which when persist in the environment and have the potential to cause adverse effect on man ,vegetation and marine life. The heavy metals present in the industrial waste water such as Pb, Cd, Cr, Ni, Zn, and are the most toxic and perilous materials among the other toxic materials from the chemical and allied industries.
Several methods have been used in wastewater treatment which includes filtration, precipitation, ion exchange and membrane filtration, Adsorption is one of the methods for removing heavy metals from contaminated effluents and the most effective among all. Carbon nanotubes (CNTs) have great potential as novel type of adsorbent of heavy metals and organic compounds such as zinc, cadmium, lead, nickel, copper, as well as fluoride and radioactive nuclides. It has the natural characteristics that influence the metal adsorption such as surface area, pore size distribution and chemical nature of their surface. Moreover, the hexagonal arrays of carbon atoms in graphite sheets of CNTs surface have strong interactions with other molecules or atoms.
The interaction is due to the strong van der Waals binding energy for molecular adsorbents.CNTs surface has a hydrophobic nature, but by the addition of some exogenous functional groups on the CNTs surface the surface area of CNTs increases and it becomes a hydrophilic material. It disperses in water very easily and excellent absorption capacity is created. The adsorption is occurring due to strong electrostatic and ?-? interactions, but the use of CNT in environmental protection application is limited due to its high production cost and low yield, but there are low cost Omani bio-waste composite material such as palm date seeds, starch and pumpkin seeds which can be used with CNTs due to its potential to be an appropriate precursor for preparation of porous carbon.
The application of low-cost adsorbents obtained from the bio wastes material as a replacement for costly conventional methods of removing wastewater pollutants e.g. Organic compounds and heavy will result in breaking industrial and economical limitations in water treatment field. It is demonstrated that carbon based material is considered as the ideal material for remediating water and have been proven to be a promising material.
The objectives of the present study are as follows:
To contribute for less expensive adsorbents and their utilization possibilities
To investigate the adsorption capacity of as-produced and oxidized CNTs for Cu2+, Cd2+, Pb2+, Ni2+, and Cr6+ metal ions.
To study the effects of contact time, initial pH, and dose on the adsorption
To investigate the adsorption isotherm and kinetics of metals’ adsorption
To investigate the maximum yield of heavy metal ions adsorption in sorbent
To Investigate the equilibrium time of each adsorption batch
Materials and chemicals
Materials and chemicals required for the experiment mentioned in Table below
Materials ; chemicals Specifications
Multiwall Carbon Nanotubes (MWCNTs) Length 20-30 nm
OD: Approximately 30 ?m Sulfuric Acid (H2SO4) Volume: 500 ml Concentrated Phosphoric Acid (H3PO4) Volume: 200 mL Concentrated Nitric Acid (HNO3) Volume: 200 mL Concentrated Potassium Permanganate powder Mass:50 g Heavy metal adsorption experiments of CNTs
MWCNTs will be oxidized by dispersion into a flask containing concentrated nitric acid and sulphuric acid solution and refluxed at 140°C for 6?h. The suspension will be washed with deionized water to remove excess oxidant. Then, the oxidized CNTs, denoted as “MWCNTs-ox”, will then be dried at 100°C and stored for further studies.
The adsorption behaviour of as-produced MWCNT and MWCNT-ox for metal ions Cu2+, Cd2+, Pb2+, Ni2+, and Cr6+ will be investigated by means of the batch experiments at room temperature (~25°C). Batch adsorption experiments will be conducted using different doses of as-purchased MWCNTs and their oxidized form, ranging from 0.1 to 4?g/L of solutions containing heavy metal ions of desired concentrations (20?mg/L) for each metal. The adsorption of metals will be then investigated in the pH range of 2–8.
Oxidation method of MWCNTs
MWCNTs (2.0g) were dispersed in 700mL of concentrated H2SO4/HNO3 mixture (V: V 3:1) and sonicated in a path sonicator for 70 minutes then cooled to room temperature. MWCNTs were washed with deionized water to reach neutral PH level. MWCNTS were then centrifuged at 20.000g for 15 min and then sediment dried at 100 overnight (24h) to obtain O-MWCNTs.
Due to the porous structure or surface of MWCNTs the adsorption of heavy metal ions will occur inside these pores, and the important role that oxidation process does is to create functional groups on the surface of MWCNTs, these groups will increase the capacity of adsorption by changing some physiochemical property which is the hydrophobic property of MWCNTs in water or aqueous solution, into hydrophilic property. Before oxidation of MWNCTs they were hydrophilic and they tend to stick to each other and aggregate as one bulk, but after oxidation they turn into hydrophilic and they have the ability to be dispersed in water or aqueous solution. The dispersion of MWCNTs will increase the surface area of each tube therefore the adsorption capacity will increase.
Techniques for characterization
Since CNTs possess a unique structure, with different types and arrays, with variety of physiochemical properties and without forgetting the Nano scale measurement. Therefore, they require a higher attention in terms of characterization and analysis,
The phase structures of CNTs will be characterized by powder X-ray diffraction (XRD). The surface properties of the CNTs before and after adsorption of heavy metals will be characterized by scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) for its elemental analysis. The size and morphology of the CNTs before and after adsorption will be elucidated by transmission electron microscopy (TEM). The functional groups of CNTs will be identified by Fourier transform infrared spectroscopy (FT-IR) analysis. Gas adsorption analyzer with Brunauer–Emmett–Teller (BET) method will be used for the surface area, pore size and volume determination. Raman spectrometry also known as a powerful tool for the characterization of carbon structures could help to qualitatively and quantitatively estimate the purity and defects in CNTs before and after the heavy metal adsorption. The detection and concentration of metals in the solution will be determined according to inductively coupled plasma optical emission spectrometry (ICP-OES).