Determination of ammonia in water and industrial effluent streams with the indophenol blue method using sequential injection analysis
ABSTRACT A suitable sequential injection analysis (SIA) analyser to monitor water quality in terms of the ammonia content in water and industrial effluent streams was developed. The system is fully computerised and is able to monitor ammonia in samples at a frequency of ca. 16 samples per hour with a relative standard deviation better than 1.8%. The calibration curve is linear between 0 and 50 mg l−1 which falls within the required analyte range. The levels of possible interferants in the water and industrial effluent streams were negligible to cause any interference on the proposed system.
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ABSTRACT: This work investigated the influence of pyrolysis temperature on biochar production and evaluated its properties for agricultural applications. Biochar yield decreased and its pore structure developed with the increase of temperature from 300 to 700 °C. Biochar produced at 300 °C was acidic whereas at higher temperatures it was alkaline. Fewer dissolved salts were contained in the biochars produced at higher temperatures. The rich nutrients, other than nitrogen, were intensified with the temperature rise. The results of (diethylenetriaminepentaacetic acid) DTPA-extraction showed the pyrolysis process abated the bioavailability of trace nutrient elements (Mn, Fe, Zn and Cu). The leaching toxicity of Pb, Zn, Ni, Cd, As, Cu and Cr in the biochars was lower than that in the sewage sludge although the pyrolysis process enriched the heavy metals in the biochars. Hence, the biochar was safer than sewage sludge as a soil amendment.Journal of Analytical and Applied Pyrolysis 01/2015; 20. DOI:10.1016/j.jaap.2015.01.010 · 3.07 Impact Factor
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ABSTRACT: One of the major problems in the analysis of ammonia (NH3) using spectrophotometric method is highly coloured water sample. A reflectometric NH3 sensor based on a facile single-step immobilisation of cobalt(II) (Co2+) ion onto high capacity Dowex HCR-W2 microspheres has been developed to enable the direct NH3 determination in highly coloured water samples. The combination of Co2+ ion-immobilised microspheres via cation exchange chemical reaction and reflectometric technique has improved the optode sensing performance with respect to linear response range and response time. Immobilised Co2+ ion, when complexed with NH3 gave a blue colouration of hexamminecobaltate(II) ([Co(NH3)6]2+) complex at pH 13. The NH3 sensor reached maximum colour intensity in ∼6 min at ambient conditions. The linear calibration curve was 60–290 mM NH3 with a detection limit of 16 mM NH3, which is suitable for direct determination of NH3-enriched leachate water samples. A good reproducibility between 5.4 and 5.9% relative standard deviation (RSD) was obtained with the probe and the sensing performance can be regenerated using buffer pH 1. The effect of potential interference ions has been investigated during the quantification of NH3 in heavily polluted sewage water. The results obtained were in good agreement with those produced by acidimetric reference method.Sensors and Actuators B Chemical 08/2012; 171-172:994-1000. DOI:10.1016/j.snb.2012.06.016 · 3.84 Impact Factor
Article: Sequential injection analysis[Show abstract] [Hide abstract]
ABSTRACT: A review is given of the principals and applications of sequential injection analysis with sections on food and beverage analysis, bioprocess monitoring, immunoassay and bioanalysis, pharmaceutical analysis, environmental analysis, chemometrics, industrial and process analysis and sequential injection renewable microcolumns. (301 references)The Analyst 09/2002; 127(8):997-1020. DOI:10.1039/B106791P · 3.91 Impact Factor