Ammonium ion removal from water by coagulation using and electrochemically prepared polyaluminium chloride

As part of advanced technologies, water companies tend to use the most effective coagulants, which will produce higher quality for the final treated waters and greater reliability. Alum and prehydrolyzed aluminium chloride with general formula Alm(OH)nCl3n-m (PAC) have been widely applied as coagulants in water treatment technologies. Their hydroxyl aluminium polymers were recognized as the most effective components in Al coagulants. Using the principles of coagulant preparation and of the electrolysis process, the method of electrochemical synthesis of the Polyaluminium chloride (E-PAC) has been proposed and carried out extensively in our previous research. In this study the coagulation properties of electrochemically obtained PAC (E-PAC) on ammonium ion removal from water was evaluated in laboratory scale and it was compared with the performance of a commercially available PAC solution and classical aluminium sulphate (alum)

Coagulation characteristics of electrochemically prepared polyaluminium chloride on humac acid removal from water

The treatment of surface natural water for drinking water production goes through the degradation of humic substances. The increasing demand of more efficient coagulation water treatment, especially regarding the removal of natural organic matter (NOM), has lead to the development of a new category of coagulants, the pre-polymerised inorganic coagulants, such as polyaluminium chloride (PAC). An alternative preparation procedure for PAC (prehydrolyzed aluminium chloride with general formula Alm(OH)nCl3n-m) is presented in this paper. Using the principles of coagulant preparation and of the electrolysis process, the proposed procedure is based on the use a new method for the preparation of electrochemically obtained PAC (E-PAC) in an electrochemical reactor, equipped with plain-plate A1 anodes and stainless steel cathodes, and AICI3 aqueous solution as electrolyte, applied with successfully in our laboratory. Coagulation behaviors of E-PAC and conventional coagulants as alum and commercial product PAC were compared, using the so-called „Jar test" procedure, in accordance with water treatment standards, to remove humic acid (HA) from deionized water with addition of lmg/L of humic acid (commercial HA powder), selected for this study, due to the fact that it is a principal component of humic substances, which are typically the major component of NOM in water supplies. As part of the applied procedures, the level of residual turbidity, the amount of total organic carbon, the UV-254 absorbance and colour were evaluated, in oerder to assess the efficiency of the coagulation process in all situations (PAC, E-PAC and alum as coagulants). The results suggest than the electrochemically obtained E-PAC can be alternatively produced by electrolysis process easily controlled, resulting a product with better properties than the commercial PAC used for comparison to remove humic acid from synthetic water

Anodic Determination of Acetylsalicylic Acid at a Mildly Oxidized Boron-Doped Diamond Electrode in Sodium Sulphate Medium

Differential pulse voltammetry (DPV) and chronoamperometry (CA) were used to detect and determine acetylsalicylic acid (ASA) at a mildly oxidized boron-doped diamond (BDD) electrode in a neutral sodium sulphate solution as supporting electrolyte. ASA determination in unbuffered medium was achieved using neutralized standard and real samples. Over the concentration range of 0.01 mM–0.1 mM, linear calibration plots of anodic current peaks in DPV and anodic currents in CA experiments versus concentration were obtained with very high correlation coefficients and good sensitivity values. The limits of detection were situated around 1 μM. The association of DPV and CA techniques with standard addition method represented a suitable option for the determination of ASA in real samples such as pharmaceutical formulations

Determination of methylparaben from cosmetic products by ultra performance liquid chromatography

A new method for the determination of methylparaben by ultra-performance liquid chromatography (UPLC) was developed. Methylparaben is often used as preservative, alone or in combination with other parabens, being added to cosmetic products, pharmaceutical products and foods to avoid microbial contamination. Due to its widespread use and potential risk to human health, assessing human exposure to this compound is of interest. A good determination and quantification of methylparaben was developed with a gradient elution using a mixture of methanol and water (60:40, v/v) within 1.455 min. Under optimized conditions, the linear working range extends over two orders of magnitude with relative standard deviations of intra- and inter-day precision below 2.3 %, and a detection limit of 0.02 ng μL-1 for methylparaben. The proposed method was successfully applied to the assay of methylparaben in cosmetic products with minimal sample preparation

Anodic Determination of Acetylsalicylic Acid at a Mildly Oxidized Boron-Doped Diamond Electrode in Sodium Sulphate Medium

Differential pulse voltammetry (DPV) and chronoamperometry (CA) were used to detect and determine acetylsalicylic acid (ASA) at a mildly oxidized boron-doped diamond (BDD) electrode in a neutral sodium sulphate solution as supporting electrolyte. ASA determination in unbuffered medium was achieved using neutralized standard and real samples. Over the concentration range of 0.01 mM–0.1 mM, linear calibration plots of anodic current peaks in DPV and anodic currents in CA experiments versus concentration were obtained with very high correlation coefficients and good sensitivity values. The limits of detection were situated around 1 μM. The association of DPV and CA techniques with standard addition method represented a suitable option for the determination of ASA in real samples such as pharmaceutical formulations

Anodic Voltammetry of Thioacetamide and its Amperometric Determination in Aqueous Media

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Simultaneous Chronoamperometric Sensing of Ascorbic Acid and Acetaminophen at a Boron-Doped Diamond Electrode

Cyclic voltammetry (CV) and chronoamperometry (CA) have been used to sense and determine simultaneously L-ascorbic acid (AA) and acetaminophen (AC) at a boron-doped diamond electrode (BDDE) in a Britton-Robinson buffer solution. The calibration plots of anodic current peak versus concentration obtained from CV and CA data for both investigated compounds in single and di-component solutions over the concentration range 0.01 mM – 0.1 mM proved to be linear, with very good correlation parameters. Sensitivity values and RSD of 2-3% were obtained for various situations, involving both individual and simultaneous presence of AA and AC. The chronoamperometric technique associated with standard addition in sequential one step and/or two successive and continuous chronoamperograms at two characteristic potential levels represented a feasible option for the simultaneous determination of AA and AC in real sample systems such as pharmaceutical formulations. The average values indicated by the supplier were confirmed to a very close approximation from chronoamperomgrams by using several additions with the application of suitable current correction factors

Electrochemical Sensing and Assessment of Parabens in Hydro- Alcoholic Solutions and Water Using a Boron-Doped Diamond Electrode

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