Carbon-/Zeolite-Supported TiO2 for Sorption/Photocatalysis Applications in Water Treatment

The role of various carbon forms, i.e., activated carbon and carbon nanotubes/nanofibers as support for TiO2 in drinking water treatment, is discussed. Also, TiO2 supported onto zeolite that acts bifunctionally as a sorbent/photocatalyst for drinking water treatment is presented. The main contaminants of natural organic matter (NOM), arsenic species, and nitrogen compounds from drinking water sources by the type of groundwater and surface water can be removed/degraded by sorption/photocatalysis using TiO2 supported onto carbon and/or zeolite. TiO2 supported on powdered activated carbon (PAC-TiO2), granular activated carbon (GAC-TiO2), and zeolite (Z-TiO2), namely, supported TiO2, was synthesized through the sol-gel method, and TiO2 and multiwall carbon nanotubes/carbon nanofibers dispersed within epoxy matrix (CNT-TiO2-Epoxy, CNF-TiO2-Epoxy), namely, TiO2 composite, were obtained through the two-roll mill method. Kinetic study results through specific mathematic models allowed to elucidate some mechanistic aspects for sorption and photocatalysis for the application in drinking water. The intercalation of the carbon- and zeolite-supported TiO2 layers into a filtering system allows to develop a self-cleaning filtering system in drinking water

Environmental friendly electrochemical determination of aspirin from alkaline aqueous solution

The electrochemical determination of acetylsalicylic acid (ASA) on multi-walled carbon nanotube- epoxy composite electrode (MWCNTs-EP) in aqueous solution was investigated using electrochemical techniques, e.g. cyclic voltammetry (CV), differentialpulsed voltammetry (DPV) and square-wave voltammetry (SWV). SWV applying allowed to reach the best performance in relation with the sensitivity for ASA determination in alkaline medium

Removal of pharmaceuticals from wastewaters by electrooxidation

The removal of the non-steroidal anti-inflammatory drug diclofenac (DCF) was carried out by electrooxidation on Dimensionally Stable Anodes (DSA) with the composition Ti/Ruo.3Tio.70 2. The DSA electrodes were obtained by thermal decomposition of the appropriate precursors. The electrolyses were carried by using solutions of 100 mg/L DCF in 0.1 M Na2S0 4 supporting electrolyte in acidic medium at various current densities and electrolysis times. The removal of DCF was assessed by recording UV-VIS spectra and chemical oxygen demand (COD) determination of the electrolysed solutions. The results showed the mineralization of the DCF during the electrooxidation on Ti/RuojTiojCb electrodes

Removal of turbidity and organic load from surface water by coagulation-flotation

The aim of this study is to monitor comparatively and operationally two drinking water treatment flows, a new based on flotation unit using prehydrolyzed aluminium coagulation agent in comparison with settling based on the conventional technological flow using aluminium sulphate coagulation agent. The new proposed and introduced flow exhibited greater drinking water treatment performance under the conditions of raw surface water characterized by low and medium loading in terms of turbidity and organic load. The new proposed technological flow allowed that all studied parameters characteristics to the drinking water for treated water to meet the requirements imposed by the legislative norms

Photocatalytic degradation of methylene blue from water using UV irradiation

The aim of this study was to investigate the influence of various parameters on the photocatalytic activity of a copper doped zeolite in the degradation of cationic dye Methylene Blue (MB) from aqueous solution under UV irradiation. The experimental studies revealed that the removal efficiency expressed in terms of discoloration and aromatic ring- opening depended strongly of the initial pH, initial concentrations of the dye solution and catalyst doses. Some mechanistic aspects have been investigated in relation with Zeta potential measurements correlated with adsorption and heterogeneous photocatalysis principles at various pH values

Electrochemical behavior and determination of arsenic (III) from water using ag-doped-zeolitecarbon nanotubes composite electrode

The electrochemical behavior of Arsenic (III) from water was investigated using Agdoped-synthetic zeolite-carbon nanotubes composite electrode envisaging its determination in the aqueous solution. The electrocatalytic oxidation of arsenic in acidic medium at Ag-doped -synthetic zeolite-carbon nanotubes composite electrode (Ag-ZCNT) was investigated by cyclic voltammetry, with different practical working pretreatment applications

Simultaneous fluoride and arsenic removal from groundwater by using aluminium sacrificial anode

The simultaneous removal of fluoride and arsenic in groundwater collected from three deep wells situated in Western part of Romania was carried out by electrocoagulation (EC) with aluminium sacrificial anode. The current density was of 156, 480 and 780 A/m2 , respectively and the electrolysis time 60 min. The removal efficiency of fluoride and arsenic was determined based on their residual concentration. Also, the specific energy consumption was calculated and it was in the range of 0.14 - 1.40 kWh/m3