Comprehensive Water Analysis

Comprehensive Water Analysis

• Aims to analyze water sample properties like hardness, chloride, TDS, pH, and sulfate levels
• Results are compared to standards set by India's central pollution control board (CPCB)

Estimation of Total Hardness

• Determines a water sample's total hardness
• Hardness arises from calcium and magnesium salts
• Temporary hardness is due to calcium and magnesium bicarbonates that precipitate and can be filtered out via boiling
• Permanent hardness is due to calcium and magnesium chlorides and sulfates
• Ethylenediaminetetraacetic acid (EDTA) forms complexes with calcium and magnesium at a basic pH (9-10)
• Ammonia buffer (NH4OH – NH4Cl) maintains the water sample's pH
• Total hardness assessed using an EDTA solution
• As EDTA is insoluble in water, disodium salt of EDTA is generally used for complexation
• EDTA provides six binding sites
• Eriochrome Black-T (EBT) indicates when complexation is complete
• Calcium and magnesium ions create a wine-red complex with EBT indicator in an ammonia buffer
• As EDTA is added, it replaces the indicator, forming a stable Metal-EDTA complex
• This releases the EBT indicator, turning the solution steel blue

Reagents, Solutions, and Apparatus needed

• Standard hard water of 1mg/mL CaCO3 equivalents
• 0.01 N EDTA solution
• EBT indicator
• Hard water sample
• NH3-NH4Cl buffer solution
• Burette, pipette, conical flask, standard flask, and burette stand are also required

Standardization of EDTA

• Titration includes pipetting 20 mL of standard hard water (1mg/mL CaCO3) into a conical flask
• Add 3-5 mL of ammonia buffer (NH4OH – NH4Cl) to maintain a pH around 10
• Add three drops of Eriochrome Black – T (EBT) indicator
• Titrate against the EDTA solution in the burette
• The endpoint is reached when a color change from wine red to steel blue occurs
• Repeat titrations to achieve a concordant titre value (V1)

Calculations for EDTA Standardization

• 1 mL of EDTA requires = 20/V1 mg CaCO3 for complexation
• 20 mg of standard hard water demands V1 mL of EDTA for complexation
• V1 defines the volume of EDTA consumed by 20 mL of hard water

Estimation of Total Hardness Using Titration

• 20 mL of the hard water is added to a conical flask, add ammonia buffer (NH4OH – NH4Cl) solution, and three drops of Eriochrome Black-T (EBT) indicator
• Titrate the mixture with standardized EDTA until the solution changes color from wine red to steel blue and repeat the titration for a concordant titre value ('V2')

Calculations for Determining Total Hardness

• 1 mL of EDTA necessitates 20/V1 mg CaCO3 for complexation
• 20 mL of the hard-water sample = V2 mL of EDTA
• Concentration calculation = V2 x 20/V1 mg of CaCO3 equivalent
• 1000 mL of hard-water consumption = V2 x 20/V1×1000/20
• Resulting Calculation= V2/V1×1000 ppm, representing total hardness

Chloride Content Estimation

• Electrolyte solutions conduct electricity due to the presence of ions
• In conductometric precipitation titration involving AgNO3 and Chloride ions, conductance slowly reduces
• This is due to chloride ions forming AgCl precipitate, preceded by sodium ions replacing silver ions, up to the equivalence point

Post Equivalence Point

• If no chloride ions are present, the conductance increases quickly due to silver ions from AgNO3
• Obtained precipitate has low water solubility
• Methods using AgNO3 for halide and sulfide ions yields good selectivity in quantitative chloride ion analysis

Materials Needed

• Use standard AgNO3 and NaCl solutions, and Burette, pipette, beaker, standard flask, burette stand, Pt electrode, a digital conductometer, and magnetic stir bar

Methodology for Chloride Estimation

• Make up an unknown chloride solution to 100 mL with distilled water, pipette 20 mL into a beaker, and add 10 mL distilled water
• Dip a conductivity cell with a known constant
• Fill the burette with ~0.01 N AgNO3
• Record conductivity of the chloride sample (0th reading). Add 1 mL AgNO3 of known concentration, stirring with a magnetic stirrer
• Repeat AgNO3 additions (1 mL each) and measure conductance
• Continue titration beyond the equivalence point (~5 mL)
• Plot conductance vs AgNO3 volume, the intersection point = AgNO3 volume required

Total Dissolved Solids (TDS) Estimation

• TDS measures dissolved solids in water samples
• Electrical conductivity (EC) indicates ionic strength in fluids
• TDS is proportional to electrical conductivity
• TDS (mg / L) = ke × EC(µS / cm), where ke is a constant, generally 0.55 to 0.85 (average 0.7)
• Use a conductivity meter to measure electrical conductivity
• Multiply the conductivity by 0.7

pH Determination

• pH measures hydrogen activity
• Difficult to measure directly, electrodes are needed for accurate pH readings
• Range is from 0 to 14
• Lower values = high H⁺ (acidic), higher values = low H⁺ activity (alkaline)
• pH 7 is neutral
• Whole pH unit = tenfold change in hydrogen ion concentration
• Rainwater: pH 5.4-6.0, and it becomes alkaline (pH of 8.0-8.5) after earth reactions
• pH is measured using a pH meter with a glass electrode, reference electrode, and KCl bridge
• Calibrate meter using at least two buffers
• Dip pH electrode and record value

Sulfate Estimation

• Used to measure the amount of sulphate in water
• Sulfate ions are converted to barium sulfate suspension
• Turbidity is measured by a nephelometer and matched with a standard sulfate curve
• Reference is provided from the EPA
• Conc. HCl, conditioning reagent, Na2SO4 stock solution (1420 ppm), and BaCl2.
• Prepare the conditioning reagent by mixing 30 mL conc. HCl with 300 mL distilled water, 95% ethanol or isopropanol, and 75 g NaCl. Add 50 mL glycerol
• Use Magnetic stirrer, Nephelometer, Stopwatch, Measuring spoon, 250 mL conical flask, and 1L volumetric flask.
• Prepare seven flasks, labeled 1-7 and Standard Na2SO4 solutions at 50, 100, 150, 200, and 250 ppm by diluting 3.5, 7, 10.5, 14, and 17.5 mL of Na2SO4 with distilled water
• Transfer them to 250-mL Erlenmeyer flasks
• Then add 5ml of conditioning reagent to the blank solution and shake to mix well for exactly 1 min and add 0.6 g of BaCl2 crystals without adding the test solution
• Calibrate turbidity
• After shaking, each aliquot is added to the corresponding vial and compared

Bomb Calorimeter for Energy Source Evaluation

• Used to estimate the heat released from a fuel or food
• Solid fuels like coal, biomass, and dry foods are collected
• The calorimeter is designed to burn samples in a controlled oxygen environment

Calorific Value (CV)

• CV reveals the energy released during combustion of a known mass
• Bomb calorimeters have a stainless steel airtight cylinder with an inlet valve for oxygen and two stainless steel electrodes
• Sample is put in a nickel or stainless-steel crucible supported by a ring attached to an electrode
• The bomb is put inside a copper calorimeter, surrounded by an airtight, water-filled jacket
• The calorimeter also contains an electrical stirrer and mercury thermometer

Bomb Calorimeter Working Formula

• Fuel weight = m g, calorimeter water = W1 g, calorimeter water equivalent = W2 g
• Initial water temperature = t1 °C, water’s final temperature = t2 °C, water’s specific heat = 4.187 kJ/kg°C
• Calibration uses Benzoic acid of GCV = 26455 kJ/g and a fine magnesium wire touching the fuel sample is then stretched across the electrodes

Steps of Bomb Calorimeter Use

• Screw bomb lid
• Add oxygen up to 25 atm
• Place bomb in calorimeter with known mass of water
• Electrically connect to a 6V battery
• Burn sample, stir and record max temperature
• Get W2g using (1)

Fuel and food preparation

• Take calibrated, known mass of an energy sample in a clean crucible
• Add magnesium wire
• Follow the same calibration as the reference sample
• Record the initial and final temperatures so the equation can be followed and used to calculate GCV

HAP Nanoparticles for Heavy Metal Removal

• Hydroxyapatite (HAP) nanoparticles are used for bio-ceramics, environmental pollution control, and more
• Experiment aims at synthesizing HAP nanoparticles from eggshell bio-waste using chemical precipitation
• It also determines their use in the removal of Ni (II) from wastewater

HAP Chemistry

• Hydroxyapatite (HAP) is Ca10(PO4)6(OH)2, with a Ca/P ratio of 1.67, a ratio below suggests a calcium deficient HAP
• Natural HAP contains trace amounts of Na+, Zn2+, Mg2+, K+, Sr2+, Ba2+, F¯, and CO3²¯, calcium-deficient forms improve
• Natural HAPs are good adsorbents for metal purification due to exchangeable ions
• Synthesis uses coral, eggshells, and fish bones

Part A: HAP Nanoparticle Synthesis From Eggshell Biowaste

• Requires cleaned eggshells, concentrated HNO3, NaOH, and (NH4)2HPO4
• Use chemical precipitation in the prepartion of nanoparticles from eggshell bio-waste
• Clean and crush eggshell and dry at 100°C and add around 5ml of concentrated HNO3 slowly
• Add 15 ml of deionized water to 4N NaOH solution so yellow solution forms
• Pour resultant solution and use filter paper to get Ca(NO3)2
• Combine NH4)2HPO4 with solution to form hydroxylapatite, maintain 9 pH level and mix with filtrate
• The precipitate is allowed to dry at 100 °C or at 900°C to get cHydroxylapatite

HAP Characterization:

• Powder XRD is employed, using a Rigaku Smartlab 3 KW diffractometer with Cu Kα radiation and a 10-80° (2θ) scan range
• Scherrer's equation is used to determine crystallite size

Estimation Procedure by Colorimetry

• Estimation of Ni2+ using dimethylglyoxime (DMG)
• Dimethylglyoxime (DMG) = pink-colored Ni(DMG)2
• Oxidization by potassium ferricyanide from brown-red, water-soluble oxidized forms, absorption is shown at 440mm

Ni2+ Removal Procedure Continued

• Employ HAP in batch adsorption
• Disperse HAP in water and gently mix and mix again and test content with reagent
• The percentage of Ni2+ ions were calculated based on initial measures for the color tests

Dye-Sensitized Solar Cell (DSSC) Creation

• Dye-sensitized (DSSC) harvests solar energy via natural dyes from fruits/flowers with TiO2
• Harvest involves using natural fruit dyes like pomegranate
• Fruits and flowers contain pigment which is the absorbing layer, the dye allows the harvest of energy

The DSSC Overview

• Absorber layer combined with TiO2, for use photo anode of the cell through monolayer junctions
• Under light, the dye injection releases 2 types of materials
• Then the development or photo engineering is constructed to enable efficient devices through support along which the powder forms with graphite

DSSC Protocols

• The conducting base coats glass with TiO2 mixed with dilute nitric acid while drying or having juice from ethanol
• Bakes the film at 70 °C and place graphite and coat a PET sheet inside KI+I2
• The electrodes are placed, connected to the electrode wire, measure voltage drop with multimeter, transparent side to the sun
• Cells connected in a series should equal 3.5V

Supercapacitor Fabrication

• It is derived from biowaste from lime peels
• To syntesize activated carbon (AC) from sweet lime-peel bio-waste and determine the diffusive controlled and capacitive current currents of the fabricated AC-based supercapacitor
• It consists of sweet lime peels, polyvinyldene fluoride (PVDF), N-methyl pyrolldine (NMP), nickel foam, nafion, Cu wires as connector, Hg/HgO Reference Electrode, Platinum foil

Capacitor Principles

• Capacitors use a charge, separated by a dielectric, more charge and efficiency
• Batteries do similar work to store electricity
• Capacitance = I (Current) x change in amount of discharge time divided by mass times the potential between the plates
• There are different forms of capacitors

Making an electric double layer capacitor

• Use metal with powdery charcoal to give areas for huge charge
• Separate plates immersed in electrolyte along a thin insulator
• Lime needs to be cut, tap washed, then rinsed with deionized water and dried
• Use powder to get fine form by grinding
• Add lime with KOH for one hour
• Remove lime and treat with 1M HCL for an hour
• Maintain lime with heat and HCL to carbonize the material
• Use machinery to measure results by combining activated carbons synthesized in a morter and adding 1ml in the semi slurry to apply to the paste