Aamir Amanat Ali Khan

Decolorization of Blue CL-BR dye by AOPs using bleach wastewater as source of H2O2

This research was focused on the investigation of the efficacy of advanced oxidation processes (Fenton, ozonation and UV/H2O2) for decolorization of reactive azo dye (Blue CL-BR) using bleach wastewater as possible source of H202. All the experiments were performed on the laboratory scale set-up. The results showed that colour removal efficiencies by UV or bleach (H2O2) alone were not so efficient. Fenton process with bleach wastewater was found to be the most effective at process conditions such as pH of 3 and H2O2/Fe2+ ratio of 24:1, resulting in 64% colour removal. Almost complete colour removal, i.e., 99% and 95% were achieved by UV/H2O2 and UV/bleach wastewater in 30 and 60 min, respectively. Ozonation proved an efficient method for decolorization of Blue CL-BR dye at alkaline pH. It was possible to achieve 98% colour removal with 30 min of ozonation at pH 9. The colour removal of dye was found to follow first order kinetics.

Pathogen Re-Growth in UASB Effluent Disinfected By UV, O3, H2O2, and Advanced Oxidation Processes

Disinfection of anaerobically treated effluent (UASB) was carried out to eliminate the enteric pathogens by using UV irradiation, peracetic acid, H2O2, O3 and advanced oxidation processes (O3/H2O2, O3/UV and H2O2/UV). Re-growth potential of these pathogens was monitored in terms of time and temperature. Inactivation of pathogens by ozone at the rate of 300 mg/h for 20 minutes approached 99%. UV irradiation resulted in 99% pathogen removal at irradiation time of 120 seconds. A dose of 170 mg/L H2O2 eliminated more than 99% pathogens. Samples disinfected with UV, H2O2 and O3 showed gradual re-growth with an increase in time and temperature (from 20 to 35°C). However, disinfection with AOPs proved to be the most effective tool resulting in reduction of treatment time taken by individual processes, also the disinfected samples showed minimal re-growth revealing the superiority of their combined effects.

Sludge granulation and efficiency of phase separator in UASB reactor treating combined industrial effluent

Sludge granulation and the effect of gas-liquid-solid separator (GLSS) design on the efficiency of upflow anaerobic sludge blanket (UASB) and upflow anaerobic sludge filter (UASF) reactors, operating at HRTs ranging from 3 to 12 h were investigated. VSS/TS ratio gradually increased in both the reactors with increasing sludge age (from 0.5 to more than 0.7 for UASB reactor and 0.012 to 0.043 for UASF reactor). X-Ray diffraction analysis of the UASF sludge showed the presence of expanding clays revealing its additional absorption capability. Fuoraphyllite and albite precipitation related to excellular polymers of the microbial shell structure, showed the extended growth of microorganisms during sludge granulation. A gradual decrease (82%-69%) in COD removal with decreasing HRT was apparent in UASF reactor. In case of UASB reactor, this decrease was marginal because addition of GLSS device significantly improved (14%-20%) the overall efficiency of the UASB reactor. GLSS enhanced the efficiency of the UASB reactor by increasing the settleability of suspended particles and accelerating the coagulation of colloidal particles due to the velocity gradient.

Bismuth-Modified Hydroxyapatite Carbon Electrode for Heavy Metal Detection in Biomatrices

Micro-analytical based sensors with complex biomatrices such as blood, urine, or saliva are of increasing interest in health-care sector because of their sensitivity, selectively and simplicity. A modified carbon electrode with hydroxyapatite (HAp) and Bismuth (II) was developed to detect Pb2+ concentration in blood sera from healthy persons. Square wave anodic stripping voltammetry was used for the detection of Pb2+ by the interacting capability of the Bi film and HAp on the electrode surface with the optimised parameters of deposition time 240sec, deposition potential –1.0 V in 0.1M acetate buffer followed by square wave potential scan from-1.0 V to-0.2V. Bi film deposited HAp-CME showed attractive electrochemical characteristics with high sensitivity for Pb2+. Clear current peaks for different Pb2+ concentrations were observed around-0.55V, with favourable signal-to-background ratio, and comparatively free from oxygen interferences.

Cellulose-Modified Carbon Electrode for In Situ Lead Detection

Increasing contamination of water by trace levels of heavy metals has become major environmental threats leading to an increased demand for the detection and monitoring of metal contaminants. In this work, modification of carbon electrode with cellulose was reported to enhance Pb2+ detection. The interacting ability of cellulose on the electrode surface was evaluated for Pb2+ by using square wave anodic stripping voltammetry. The deposition potential of –1.0 V in 0.1M acetate buffer for 240 sec, followed by square wave potential scan from-1.0 V to-0.2V were used. Stripping voltammogram showed current peaks corresponding to Pb2+. The sensitivity and selectivity of the modified electrodes for Pb2+ were also determined.

Screen-Printed Carbon Electrodes for the Detection of Boldenone

Boldenone (androsta-1,4-dien-17-ol-3-one), an androgenic anabolic steroid (AAS), is intensively used for growth promoting purposes in animals for meat production and as a performance enhancer in athletics. Its use is prohibited either in animals intended for human consumption or directly for humans, as most of the anabolic steroids are completely metabolized. The current method of detection, such as the mass spectrometry coupled with gas chromatography or liquid chromatography are sensitive, highly specific and are popular methods of detection. However, these have some intrinsic drawbacks such as the requirements of complicated and expensive instrumentation, time consuming and production of narrow detection limits. Boldenone and its metabolites in urine samples of animal matrices can be detected by means of electrochemical methods using tunable and chemically-modified screen-printed carbon electrodes (SPCEs).

Carbon-modified electrode for ultra trace determination of Cd (II) in aqueous solution

Increasing contamination of water by trace levels of heavy metals has become major environmental threats leading to an increased demand for the detection and monitoring of metal contaminants. In this work, modification of carbon electrode for Cd2+ detection using square wave anodic stripping voltammetry was reported. The deposition potential of −1.0 V in 0.1M acetate buffer for 240 sec, followed by square wave potential scan from −1.0 to −0.2 V were used. Stripping voltammogram showed current peaks corresponding to Cd2+. The sensitivity and selectivity of the modified electrodes for Cd2+ were also determined.