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Last Updated: 27-02-2025
1. Fourier transform Infrared Spectrophotometry (FTIR)
For functional unit determination, the Shimadzu Fourier transform Infrared Spectrophotometer- FTIR 8400 S was used. Samples were weigh in at 0.01 g and homogenized with 0.01 g KBr anhydrous by mortar agate. The mixtures were pressed by vacuum hydraulic (Graseby Specac) at 1.2 psi to obtain transparency pellet. Scanned sample passed through infra red, where its continuing wave by detector that connected to computer and given described of tested sample spectrum. Samples were usually scanned in the absorption area of 600 to 4000 cm-1. The results of analysis consisted of chemical structure, molecular binding form and certain functional groups of tested sample as basic of spectrum type.
2. UV Spectrophotometer
The T70 PG Instruments’ UV- Spectrophotometer was used to analyze the samples at different wavelength and absorption the Spectrophotometer was first switched on and allows to stabilize before the calibration was done using distilled water and a black body. After calibration the wavelength was set to 330nm and the corresponding absorption was displayed after pressing the key for absorption. This step was followed for other wavelength until it gets to 900 nm.
3. Gas chromatography/mass spectrometry (GC/MS)
Samples (digested) were analyzed by gas chromatography/mass spectrometry (GC/MS), using Agilent-Technologies (Little Falls, CA, USA) 6890N Network GC system, equipped with an Agilent-Technologies 5975 inert XL Mass selective detector and Agilent- Technologies 7683B series auto injector. The separation was performed on Agilent Technologies capillary column HP5MS (30 m × 0.25 mm; film thickness 0.25 μm). Sample volume of 1.0 μL was injected into the column with split ratio 100:1. The carrier gas used was Helium at a flow rate of 1.2 mL min-1. The column temperature was programmed from 150oC to 250 oC at a linear ramp rate of 4 oC min-1, while the initial and final hold up time was 1 and 5 min, respectively. An electron ionization mode, with ionization energy of 70 eV, was used for GC/MS detection. Injector and MS transfer line temperature were set at 250 oC and 260 oC, respectively. The scanning mass range was selected from 30-550 m/z (mass-to-charge ratio). The unknown samples were identified on the basis of matching of their relative retention times with those of standards (Sigma Chemical Co., St Louis, MO, USA). Samples were further identified and authenticated using their MS spectra compared to those from the NIST mass spectral library of the GC/MS system.
4. X-ray fluorescent (XRF) X-ray fluorescent (XRF)
Sample cup was prepared with propylene thin film, ensuring smoothness of the thin film surface.
Pulverized sample was poured into thin film covered cup with sample filled to a third of the sample cup (approx. 5g). The lid of sample cup was covered and it was ensured that there wer no leakages or loose particles on thin film layer and also lids are tightened shut. The sample was then inserted into sample turret of Genius-IF Xenometric XRF sample chamber. The X-ray Lamp was then powered and allowed to stabilize in 2 minutes On the RUN tab, Voltage and Emission current values were set to ensure that observed dead time is between 35-40kv; The analysis was then RUN to obtain spectrum data. XRS-FP Crossroad scientific Software was then open and the Master Oxide.tfr file was uploaded then obtained Spectra file of sample was process then saved and printed to PDF file.
Operation of the Agilent 4100 MP-AES
It involved the use of compressed air, high microwave energy and flammable liquids. The plasma is extremely hot (about 6000°C) and operates using high levels of microwave energy. The plasma emits high intensity light. The microwave excitation assembly is designed to reduce microwave radiation to safe levels while still allowing easy installation of the torch and viewing of the plasma. The various indicator lights are colour coded to represent the status of the instrument. The sample is first digested with 12ml of Aqua Regia (9ml conc nitric acid + 3ml conc hydrochloric acid) for 20 minutes at 100oC.
the MP-AES was then powered and the software was uploaded, while the gas lines connected to the MP-AES was set to supply at a pressure of 4.6 bars. The sampled Prepared for the analysis was then brought forward. The MP-AES was then Calibrated with the standard solution of the metals to be analysed and the calibrated curve was plotted out. Worksheet was then opened and the samples was ran one after the other then the results were printout
5. High-performance liquid chromatography (HPLC)
Separation of sample was performed by HPLC analysis, using a Thermo Scientific System equipped with a Star Solvent Delivery System 230, Injector Rheodyne 7125, Pro Star 330 (UV – Photo Diode Array Detector). Chromatographic separation was performed on a Zorbax ODS column (250 x 4.6 mm i.d. 5 μm) (Agilent, USA). The flow rate was set to 0.9 mL/min. Operating conditions were as follows: column temperature, 20 °C, injection volume, 20 μL, UV-PDA detection at 278 nm. Before injection, extracts were filtered through 0.45 μL Nylon Membrane filter (Supelco, USA). Detection was performed with UV PDA detector by scanning from 278 to 360 nm.
6. BIO Portable Gas Analyzer
The equipment RASI700 BIO Portable Gas Analyzer (2016 Eurotron Instruments (UK) an ISO9001:2008 company) was powered and allowed to initialize for 60 seconds. After the initialization it was allowed to stabilize for five minutes. The rubber tube was then connected to the gas sample point (gas Bag or Gas outlet point from gas vessel) and the USB cord from the analyzer was connected to the computer. The gas was opened and allowed to flow into the sensor which then amplified the signal and then the reading was displayed for the whole gas present and sensed by the analyzer.
The save button was pressed and the data logged in the analyzer. The software was opened on the computer and the whole data was then printed on PDF. The system was switched off and the valve to the gas bag was closed. The analyzer was allowed to be free of any gas and then purged with nitrogen before it was shut down.
7. Scanning Electron Microscope – Energy Dispersive X-ray Spectroscopy (SEM-EDS)
The Scanning Electron Microscope energy dispersive X-ray spectroscopy (SEM-EDS) Phenom Prox model, manufactured by phenomWorld Eindhoven, Netherlands was used to carry out the morphology analysis. Sample is placed on the Aluminium holder stub using sticky carbon tape. The sample was insulated using gold and then grounded electrically. The samples each are then labeled on their stub, then dried in the oven at 60oC. Nitrogen line was opened at 50 psi and the vent button is pressed to fill the area with nitrogen for proper purging of the chamber. The sample holder stub was then placed in the sample chamber holes and the door was shut and the rotary pump picked and a vacuum of 5 x 10-5 Pa was created. The filament light was switched on and the monitor too automatically switched on. At this stage, the accelerator voltage was 15kV and the filament burned out. The atoms on the surface are excited by the electron beam, emitting specific wavelengths of X-rays that are characteristic of the atomic structure of the elements. An energy dispersive detector (a solid-state device that discriminates among X-ray energies) can analyze these X-ray emissions. Appropriate elements are assigned, yielding the composition of the atoms on the specimen surface. The lowest scan mode of 10x is picked and the TV scan clicked. The magnification is then taking to 1000x at a slow scan, 2000, 3000 to 5,000. The Energy dispersion spectrum scan on the intensity of each of the element present and gives the molar concentration in %, then Image was saved. This procedure is called The Scanning Electron Microscope Energy dispersive X-ray spectroscopy (SEM-EDS) and is useful for analyzing the composition of the surface of a specimen
Sample Preparation
Metallic Samples have a certain affinity for the electromagnets within the SEM. This affinity may be strong enough to pull the sample from the stub and up into the detector region. This will cause degradation of imaging capability and will require a service technician to remove this material from the detector. To avoid this scenario, the sample was firmly fastened to the SEM stub
Loading samples
It was ensured that the sample was properly mounted and immobilized on the stub. The height adjustment ring of the sample holder was turned counter-clockwise until the mounting surface is in the highest position and the stub pin was inserted into the hole on the mounting surface, using the tweezers. Also, it was ensured that the stub was inserted in such way that the flat of the stub is seated on the mounting surface. The sample was lowered by turning the height adjustment ring clockwise The sample was positioned correctly as it was at 2 mm below the top surface of the holder, since each one of the vertical marks on the adjustment ring corresponds to 0.5 mm, thus, rotating the adjustment ring by 4 marks lowered the sample by 2 mm. The best resolution was obtained when the sample is positioned 2 mm below the holder surface. The holder surface allows the user to optimize the trade-off between maximum field-of-view (minimum magnification) and image resolution (maximum useful magnification).
The door was opened by pushing the handle upward. The handle was held and the door was raised to its fullest extent and the sample was inserted into the sample holder slot. The sample holder was inserted correctly when the SAMPLE LED lights up green and the message ‘Please load sample’ disappears from the Image screen. The door was closed by sliding it down firmly with little initial force. The door locked automatically when a‘ lights up orange came up, then the sample is loaded and ready for imaging. The Phenom was re-activated and the sample automatically moved to the optical imaging position without sample holder inserted OK button was clicked to confirm The sample holder was then activated and its name was displayed when the holder is inserted.
Optical imaging
After the Phenom door was closed, the sample was transferred automatically to the optical imaging position. The optical camera was activated and the image was displayed in the main viewing window of the Image screen. The part of the sample that was magnified in the main viewing window was displayed in the optical overview window.
Adjusting focus
Touch to activate focus adjustment.
A focus slider appeared, showing the current focus setting. Rotate the rotary knob was rotated to adjust the focus of the optical image. Adjustment was made visible by the slider. the rotary knob was then pressed to select fine focus. An ‘F’ appears on the button and focus adjustment then took in small steps. The rotary knob was pressedagain to return to normal (coarse) focus.
Adjusting magnification (ProX / Pro)
A magnification slider showing the current magnification setting was pressed and the rotary knob was pressed to adjust the magnification of the optical image. The adjustment was made visible by the slider.
Storing images
Images was stored on a USB 2.0 flash drive (USB Flash drive) as well as on Windows.
Selecting storage location
When a USB Flash drive is inserted into one of the Phenom USB ports from SETTINGS in the screen selection bar, the Settings screen appears and the USB was cliked then the images was stored on the USB 2.0 flash drive.
8. Brunauer–Emmett–Teller (BET)
Sample Preparation.
QUANTACHROME NOVA4200e Made in USA.
Properly weigh the sample into the sample cell. Insert the filled sample cell bulb into the heating mantle. Place the clamp around the mantle so that the sample cell is held firm. Insert the sample cell stem into the sample preparation station. Tighten the knurled ring by turning it clockwise to secure the sample cell in the preparation station. After the sample cell(s) secured in the preparation station, initiate out gassing by entering the control panel menu on the instrument, set the outgassing temperature to 2500c and instruct the system to start degassing for 3hr and switch on the heater. When the sample has out gassed for 3hour’s turn off the heating mantle, Allow the heating mantle and the sample cell cool. Once the heating mantle has cooled, unload the out gas station and remove the samples. Reweigh the sample cell to determine the post out gas sample weight. Sample Analysis
Fill dewar to the internal upper mark with liquid nitrogen, place the sample cell containing an out gassed and weighed sample into the analysis station to be used for analysis! Complete all the fields/selections on the start analysis ‘’Sample’’ menu. Also complete point selection and tagging on the start Analysis ‘’Points’’ menu! Complete fields on the start Analysis ‘’Equilibrium’’ menu! Field defaults can be used for BET measurements! When all fields are completed on the start Analysis Menu, Click ‘’Start’’ to begin the analysis.
9. X-ray diffraction (XRD)
The XRD Rigaku MiniFlex 600 XRD Diffractometer was powered and from the panel, the voltage and current were set at 30kV and 15 mA. The temperature was set at 21-23oC. The computer system was switched on and the software of XRD, TUMI was double clicked to run. The settings dialogue was clicked and all the required setting of power and temperature were checked to correspond to that of the XRD. The analyzed material was finely ground, homogenized, and average bulk composition is determined. The powdered sample was then prepared using the sample preparation block and compressed in the flat sample holder to create a flat, smooth surface that was later mounted on the sample stage in the xrd cabinet.
Sample was poured into the sample holder and then placed in the sample chamber column. Then the door was shut and confirmed from the computer. The sample was analysed using the reflection-transmission spinner stage using the Theta-Theta settings. Two-Theta starting position was 4 degrees and ends at 75 degrees with a two-theta step of 0.026261 at 8.67 seconds per step. Tube current was 40mA and the tension was 45VA. A Programmable Divergent Slit was used with a 5mm Width Mask and the Gonio Scan was used.
The intensity of diffracted X-rays is continuously recorded as the sample and detector rotate through their respective angles. A peak in intensity occurs when the mineral contains lattice planes with d-spacings appropriate to diffract X-rays at that value of θ. Although each peak consists of two separate reflections (Kα1 and Kα2), at small values of 2θ the peak locations overlap with Kα2 appearing as a hump on the side of Kα1. Greater separation occurs at higher values of θ. Typically these combined peaks are treated as one. The 2λposition of the diffraction peak is typically measured as the center of the peak at 80% peak height. Results are commonly presented as peak positions at 2θ and X-ray counts (intensity) in the form of a table or an x-y plot (shown above). Intensity (I) is either reported as peak height intensity, that intensity above background, or as integrated intensity, the area under the peak. The relative intensity is recorded as the ratio of the peak intensity to that of the most intense peak
(relative intensity = I/I1 x 100 ). The result obtained was then match with different library, such as the NIST and PubChem in order to get the chemical structure, name, and other physicochemical properties
10. Digital Signature Certificate (DSC)
Sample Preparation Procedure
The sample was thoroughly dried in the solid state to avoid damaging the equipment. Weigh The sample being tested was weighed to 2 mg in a Tzero hermetic aluminum pan. It is best to place the sample directly in the pans, transferring the sample from the weigh paper to the pan can lead to a loss in material. The lid was placed on the pan. It was ensured to place the lid with the indention facing down then the covered pan was placed in the blue holder, assuring that the lid is flush with the top of the holder.
The holder was then placed under the press with lid flushed with the top of the holder. Then the handle was pulled down, thus sealing the pan and lid. Repeat with an empty pan to be used as a reference.
DSC Procedure
The sealed pans were placed in the sample tray, taking note of the slot number and the reference pan was placed in a reference slot also noting the slot number. The reference pan was an empty sealed pan and was used for multiple runs. The power to the cooler was turned on and was ensured to be on event mode.
The software was opened, TA Universal Analysis on the desktop of the computer. In the Control tab, down to event and press the ‘On’ was clicked. This will start the cooler. The ‘Go to standby temp’ was pressed so that the cell does not freeze. The temperature of the cell indicated in the status bar.
The nitrogen gas tank was turned on, and held at 20 psi and the sample purge flow was set at 50 ml min-1.
On the program in the center panel named “ ” the data for the sample that was running was entered. and all the information needed were filled out which includes: sample name, sample weight, sample slot number, reference slot number, and data storage location.
On the second tab, Procedure, the parameters for the operating procedure were entered.
To adjust the procedure type, Test wa clicked and from on Editor to set the temperatures, ramp rates, holding times, cycle names, etc.
At this time the procedure was saved to be used in further experiments. On the far right panel, Experiment, runs was added. After inserting all of the sample information and the runs are in the appropriate order the program was started. There was an arrow next to the run that will begin first.
When the program ends, the cooling system was automatically turn off. However, the nitrogen tank was turned off after the test.
11. Dynamic light scattering (DLS)
Zetasizer nano-particle analyzer (series Malvern nano ZS) supplied by Malvern instruments ltd., UK was used to determine the size distribution of the given sample. The results were analyzed using standard software Dispersion technology software, version 4.00. The instrument performs size measurements using a process called Dynamic Light Scattering (DLS), also known as PCSPhoton Correlation Spectroscopy, measures brownian motion and relates this to the size of the particles. It does this by illuminating the particles with a laser and analyzing the intensity fluctuations in the scattered light. As DLS is sensitive to the intensity of light scattered by particles, and larger particles scatter more light than small particles, then the DLS is very sensitive to the presence of aggregates, and hence, this technique is an excellent basis for studying the stability of nano particle size distribution. 0.5g of sample was place into the sample holder and the place on the analysis chamber and cover it, on the cheallar and allowed it to cool to 15 degree Celsius then on the desktop computer connected to the equipment and double click on the equipment shortcuts on the desktop computer to allowed you operate the system, input all the information about the sample and Open the nitrogen follow rate 20 finally click on start to start the analysis.
12. CHNS/O Analyzer
The elemental analyzer ELEMENTRAC CS-i was used to measures the carbon and sulfur concentration In the induction furnace of the elemental analyzer the sample is melted in a pure oxygen atmosphere, causing sulfur to react to sulfur dioxide (SO2) and carbon to a mixture of carbon monoxide (CO) and carbon dioxide (CO2).Individual control of the oxygen supply during inductive combustionA lance flushes the entire oxygen flow to the center of the crucible to ensure complete oxidation of the carbon and sulfur contained in the sample (solid samples)Oxygen flow is supplied through the combustion chamber to avoid swirling and loss of sample material (dusty samples)Sample volumes of 50 mg to 1000 mg are typical for C/S analysis. The sample is weighed in a ceramic crucible and accelerators like tungsten are added. The geometry of the sample (e. g. wire, powder, pin etc.) is not essential for a reliable analysis. The ceramic crucible is then placed on the pedestal and the analysis is started via the ELEMENTS software. The software controls all subsequent steps like combustion and evaluation.45-60 seconds after the analysis has started, the measured carbon and sulfur concentrations are available for export as a report
13. Thermogravimetric Analysis
TGA of the biomass residues was performed using a TG analyzer (TGA-Q500 series, TA instruments) at standard pressure. The sample was first dried to constant weight at 103°C to remove all moisture present then pulverized and silver to 50microns size prior to the analysis. About 10.0 mg of each sample was placed in platinum crucibles in the furnace chamber of the TGA and heated linearly at a given heating rates, (5, 10, 15, 20, 25, or 30 °C/min) from ambient room temperature to 950 °C. Nitrogen gas was opened and allowed to flow throughout the chamber of the furnace at a flow rate of 30 mL/min. This was used to purge the system and also provided the inert atmosphere for the experiments. The Thermogravimetric analysis then produced a curve, that shows the effect of temperature (or time), presented on the x axis, on the weight of the sample (the y axis). The weight is usually expressed in terms of the percentage of the sample that remains, versus the weight at the start of the experiment, at a given temperature/time. The results also include a second y axis on the graph which presents the data for the first derivative of the TGA curve. This is known as the Derivative Thermogravimetric Analysis (DTA) curve and represents the rate of change of mass with respect to temperature. The DTA curve often allows for easier visual interpretation of the data, as periods of large mass change can be seen with more clarity.
14. Nuclear Magnetic Resonance (NMR)
The solvent used: Deuterated xxx
Equipment name: Nanalysis 60MHz NMR
Equipment model: Nanalysis-X685
Machine frequency: 60MHz
Few grams of the sample was dissolved in 0.5ml of the deuterated solvent. The mixture was transferred in an NMR tube and the tube was place in the NMR machine and scanned for the analysis.