Detection of Hydroxyl
-
amine in Water Effluent of Paper
Recycling Industry
Madhurani Shukla* and Kishore K. Tiwari
Department of Chemistry,
*Govt. College Gobra Navapara, Dist-Raipur 493881, C.G., INDIA. Govt. Nagarjuna P.G. College of Science, Raipur 492010, C.G., INDIA.
Corresponding author- shukla.madhu55@gmail.com.
(Received on: January 30, 2018)
ABSTRACT
A new simple, sensitive and economical spectrophotometric method is proposed for the determination of trace amount of hydroxylamine at microgram level in water effluent of paper recycling industry. Hydroxylamine has been determined by its oxidation to nitrite by using known excess of potassium iodate. KIO3 in acidic medium bleaches the methyl red dye. A known excess of potassium iodate was reduced when treated with hydroxylamine and methyl red is used for the determination of unreacted potassium iodate. The absorbance of the methyl red dye after the reaction was monitored spectrophotometrically at 520 nm. Beer’s law was obeyed over the concentration range of 1-10 µg of hydroxylamine in an overall aqueous volume of 20 ml with a correlation coefficient of - 0.999. The proposed method was successfully applied for the detection of Hydroxylamine in water effluent of paper Recycling industry.
Keywords: Spectrophotometer, Hydroxylamine, Methyl red, Potassium iodate, Hydrochloric acid etc.
INTRODUCTION
Hydroxylamine is unstable, white crystalline compound, an explosive, hazardous having hygroscopic in nature. It is a reactive chemical having one or more replaceable hydrogen atom.1-2 Hydroxylamine reactivity is very important because of their reducing
industrial utilization and biological function, many methods have been developed for the determination of hydroxylamine quantitatively.3-5 Hazardous effect of hydroxylamine
occurred in an occupational disease like Asthma, OA caused by hydroxylamine released in the paper recycling industry. Paper recycling is a environmentally needed process. The recycling process of paper is very complex and required a wide range of chemical processes. Hydroxyl amine used in de-inking process to the production of recycled paper 6. It has been determined
by its oxidation to nitrite by using a known excess of potassium iodate. In the proposed method, an effort was made to develop simple spectrophotometric method with greater precession, accuracy for the analysis of Hydroxylamine in environmental samples.
MATERIAL AND METHODS
Apparatus
A systronics 166 spectrophotometer with matched cells was used for spectral measurements. Calibrated glassware was used during experiments.
Reagents
All chemicals used were of Anal R grade or the best available quality. Double distilled water has been used throughout the study for sample preparation and dilution of various reagents.
A: Hydroxyl amine solution -0.2106 gm of Hydroxylamine hydrochloride was dissolved in water and making the volume up to 100ml to give stock solution corresponding to 1000ppm. Experimental standard solutions were prepared by appropriate dilution of stock solution.
B: Hydrochloric acid solution- 0.5 M aqueous solution was prepared.
C: Potassium iodate solution- 0.1% potassium iodate (Merck) aqueous solution was used.
D: Methyl red-0.01% methyl red indicator solution were used. This indicator solution will be prepared by 25 mg methyl red (Merck) warm with 0.95 ml of 0.05 N NaOH and 5 ml of 50% ethanol. This solution is diluted up to 250 ml by 50% ethanol solution.
Procedure
Fig-1: Absorption spectra of the dye
RESULTS AND DISCUSSION
Spectral characteristics
Various oxidizing agents i. e. potassium iodate, potassium bromate and hydrogen peroxide etc are used for oxidizing the methyl red dye. Quantitative bleaching of methyl azo dye by these oxidizing agents is widely used for their spectrophotometric determinations. In proposed method reaction between potassium iodate and methyl red (4-dimethylaminoazobenzene-2-carboxylic acid) is use for the spectrophotometric determination of hydroxylamine. Methyl red decolorized by potassium iodate in acidic medium. Decolourisation is due to oxidation of methyl red. Hydroxylamine will be oxidized with a known excess of iodate in hydrochloric acid medium. In the absence of hydroxylamine a known excess of potassium iodate bleaches the methyl red dye. The reaction between methyl red and iodate in acidic medium was fast. When trace amount of hydroxylamine was added to the reaction mixture, reaction between methyl red and iodate was decreased, this was due to the fast reaction of hydroxylamine and potassium iodate, which inhibited the reaction of MR with iodate. When concentration of hydroxylamine increased then decreasing of absorbance occur at 520 nm. The absorbance change was reduced considerably in presence of hydroxylamine, this method applied for the detection of hydroxylamine. The mechanism of proposed reaction can be given as follows:
3NH2OH +2KIO3 2KI +3NO2- + 3H2O+3H+
Potassium iodate involve reduction to iodide in acidic medium in presence of hydroxylamine. This Iodide can oxidize to ICl which can be stabilized as ICl2- in presence of
iodate in acidic medium. This ICl2- can bleaches methyl red. Increasing concentration of
intensity of inhibition depends upon the amount of hydroxylamine in the reaction mixture. This specific property allows developing method for the detection of hydroxylamine.
Adherence to Beer’s Law, Molar absorptivity and Sandell’s Sensitivity: In the proposed method, a linear curve between concentration of hydroxyl amine and change in absorbance was obtained. Beer’s law obey the concentration range of 1-10 µg of hydroxylamine in an overall aqueous volume of 20 ml with a correlation coefficient of -0.995 (Fig-2). Sandell’s sensitivity was found to be 0.0004µg cm-2. The molar absorptivity is
calculated to be 1.55×105 Lmol-1cm-1.
Fig-2: Calibration curve for the determination of hydroxylamine
Effect of the variables: The effective variables including the reagents concentration, ionic strength, time and temperature must be optimized to obtain maximum advantages. Every parameter was optimized by setting other parameters as constant to get more sensitive results.
Effect of temperature: It was observed that in this reaction absorbance was found to be decreases as increasing temperature. The reason of decreasing absorbance may due to instability of nitrite ion at high temperature. It was much better to carry out the determination at room temperature by using thermostat.
Reproducibility: The reproducibility of above method was checked by seven replicate analysis in seven days. (Table-1) The standard deviation and relative standard deviation of 5µg/20ml hydroxylamine solution were found to be ±0.00145 and 0.267 % respectively.
Table-1: Reproducibility of the method (Conc. Of Hydroxylamine 5µg/20ml)
Effect of foreign species: The selectivity of the developed method observed by determining effect of various interferring species on the determination of 0.25 µg ml-1 hydroxylamine. It
was observed that SCN-, I- ,SO
3- - ions interfere in hydroxylamine determination. Interference
of this ions removed by using an anion exchange resin (Merk). An impotant potential interference is hydrazine in the determination of hydroxylamine. In the developed method sodium tellurite solution added which oxidize hydrazine to nitrogen. The solution was heated with 1ml of 0.2% sodium tellurite and reduced tellurium was removed by centrifuge process before addition of potassium iodate solution. Nitrite interference was overcome by using 1ml of 0.5% sulphamic acid.7 Tolerances limit of various interferring ions and species in
hydroxylamine determination are summarized in Table-2.
Table-2: Effect of foreign species on determination of hydroxylamine (Conc. Of Hydroxylamine 5µg/20ml)
Foreign species *Tolerance limit (ppm) Foreign species *Tolerance limit (ppm)
Hydrazine 0.1 NO2- 100
Na+, K+ 1000 Phosphate 900
Mg++, Al+++ 1000 Borate 1000
Pb++ 900 SCN- 10
TeO3- - 1800 SO3- - 10
Cd++ 800 I- 10
*=The amount having an error of ±3% in the absorbance value.
APPLICATIONS
The proposed method was applied for the detection of hydroxylamine in various samples. The accuracy of the method was checked by recovery test to the different water samples. The recovery values are found about 98-100% which show good agreement with the reference method. (Table-3) The proposed method was applied for the determination of hydroxylamine in effluents generated by paper recycling industry. Waste water samples of recycled paper industry are collected from Chhattisgarh viz. Hanuman Agro Private Ltd. Paragoan, Dist- Raipur (C.G.). Hydroxylamine is used as de-inking process in this industry. Occupational Asthma found in workers caused by NH2OH in paper recycling industry.
Samples (water) collected at different times were tested for NH2OH. 1 ml of this sample water
was taken in to 100ml calibrated flask which was diluted using distilled water up to mark. 1ml of aliquot of sample solution was used for NH2OH determination by present method as well
as by reported method8. The samples show NH
2OH concentration equivalent to the results
obtained by the reported method. (Table- 4)
Table-3: Determination of hydroxylamine in different water samples (n=5) Sample Hydroxylamine Added (µg) Hydroxylamine Found (µg) Recovery (%) Runoff water 4.0
5.0
3.98±0.4 4.95±0.4
99.3 98.7 Tube well water 6.0
7.0
5.97±0.3 6.98±0.4
99.4 99.6 Tap water 4.0
5.0
3.95±0.3 4.98±0.3
Table-4: Detection of hydroxylamine in water effluent from paper Recycling industry
Samples
Hydroxylamine found Present method Reported method8
Sample-1 Sample-2 Sample-3 0.094 µg 0.089 µg 0.072 µg 0.090 µg 0.087µg 0.070 µg
Table-5: Spectral characteristics of the proposed method
Parameters Results Maximum absorbance
Beer’s law concentration range Molar absorptivity
Sandell’s sensitivity Standard deviation Relative standard deviation Correlation coefficient Slope (m)
Intercept (c) Relative error Absolute error Limit of detection Limit of quantification
520nm 0.05-0.5 µg/ml 1.55× 105 Lmol-1cm-1
0.0004 µg cm-2
± 0.00145 0.267 % -0.999 -0.09164 1.024 0.01 0.01 0.039 µg ml-1
0.120µg ml-1
CONCLUSION
The proposed method has been found to be more selective and sensitive then other reported method. Detection of trace amount of hydroxylamine by using potassium iodate, which is a simple, inexpensive, easy available and non toxic reducing agent. This method is free from the commonly used pesticides interferences. The method was effectively applied for the detection of hydroxylamine in water effluent of paper recycling industry and various environmental samples.
ACKNOWLEDGEMENT
The authors are thankful to Principal and Head, Deptt of Chemistry, Govt. Nagarjuna P.G. College of Science, Raipur (C.G.) for providing laboratory facilities. The authors are also thankful to Librarian Central library, Pt. Ravishankar Shukla University, Raipur for providing library facilities.
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