A parametric evaluation of the removal as(III) and as(V) from aqueous water by red mud

In the present study, removal of arsenide (As(III)) and arsenate As(V) ions from water/wastewater by adsorption on red mud is investigated. Laboratory experiments were carried out to analyze removal capacity of the adsorbents, to achieve adsorption isotherms and kinetic parameters. Optimum doses of adsorbents, pH dependence of solutions, and contact time have been discussed. This study proposes the potential adsorbent material for water/wastewater which is contaminated with As species

Synthesis of titanium dioxide nanoparticles and their application for simultaneous photocatalytic oxidation of As(III) and sorption of As(V)

In this study, the effectiveness of TiO2 nanoparticles in removing arsenic species from water was enhanced by the photocatalytic oxidation by conversion of As(III) to As(V), which adsorbs more strongly onto the solid phase of adsorbent than As(III). Anatase nanoparticles were synthesized by using sol-gel method and the synthesized nanoparticles were characterized by X-ray diffraction and scanning electron microscopy. Batch adsorption experiment was carried out to analyze As(III) removal capacity of the anatase nanoparticles with and without presence of photocatalytic oxidation reaction. The maximum % of removal of As(III) was found ~56% at pH 6, respectively, when 1 g l-1 anatase nanoparticles were used at the As0 1 ppm without presence of photocatalytic oxidation reaction. In contrast, over 94.7% As(V) have been removed by anatase nanoparticles in a period of 120 min UV-light irradiation. Using photocatalytic oxidation process, As(III) removal from water was improved by UV-irradiation

Preparation of graphene oxide/titanium dioxide nanocomposites and its adsorption for AS(III) ions

Arsenic is a naturally occurring element, which is found in both in natural waters and industrial waters. Graphene oxide/Titanium dioxide (GO/TiO2) nanocomposites were prepared by using hydrothermal technique, their structure was observed and their adsorption performance for As(III) in water was evaluated. X-ray diffraction and Raman spectroscopy spectra confirmed the anatase structure of the TiO2 nanoparticles. The adsorption system is mainly depended on the As(III) concentration and follows a pseudo second-order kinetic model. The initial adsorption was rapid and reached equilibrium after 20 min. The overall equilibrium data were well fitted to Langmuir model for the nanocomposites. The adsorption results indicated that the GO/TiO2 nanocomposites can be a good adsorbent material to treat water that contaminated with As(III)

A Case of Acute Disseminated Encephalomiyelitis

Acute disseminated encephalomyelitis is a demyelinating central nervous system disease which is characterized by multifocal lesions of the white matter. Vaccination as well as some viruses, bacteria and other infectious agents are thought to be responsible for the etiology of the disease. A seven year old male patient developed fever, headache, vomit, abstractedness following an episode of mumps and otitis media. The diagnosis was made according to some laboratory findings and clinical follow up. The patient recovered dramatically after treatment with intravenous immunglobuline and corticosteroids. This case reveals an importance because it is a rare cental nervous system disease which can be threated easily

Comparative study of arsenic removal efficiency from water by adsorption and photocatalytic oxidation with titanium dioxide

Titanium dioxide, a well-known adsorbent material, has been extensively tested in environmental applications, especially in separation technologies. In the present study, TiO2 nanoparticles were synthesized by using sol-gel method for removing arsenic ions from water. Several water/titanium molar ratios were prepared in order to obtain optimum crystalline structure, morphology, and particle size of titanium dioxide nanoparticles. Two types of TiO2 minerals which were rutile and anatese were mainly synthesized at different calcination temperatures. After characterization of synthesized powders by X-ray diffraction and scanning electron microscopy (SEM), batch adsorption experiments were carried out to analyze removal capacity of the titanium nanoparticles. The maximum % of removal of arsenic was found ~77% at pH 3, respectively when 0.1 g rutile type TiO2 nanoparticles were used at the As0 5 ppm. Anatase type of TiO2 nanoparticles had also closer adsorption capacity which was ~63% at pH 6 with the same initial arsenic concentration. In the light of experimental results, titanium dioxide nanoparticles (TiO2) are found as a promising adsorbent material for arsenic removal from water. However, the effectiveness of TiO2 nanoparticles in removing arsenic species from water have been enhanced by the photocatalytic oxidation by conversion of arsenide ions (As3+) to arsenate ions (As5+), which adsorbs more strongly onto the solid phase of adsorbent than arsenite ions (As3+). Therefore, in the present study the photocatalytic oxidation of As3+ to As5+ is investigated in UV-illuminated and solar irradiated TiO2. Residual arsenic concentrations of the solutions treated with titanium dioxide nanoparticles were measured with a Varian, Vista-Pro CCD simultaneous inductively coupled plasma ICP-OES spectrophotometer. The adsorption isotherms, thermodynamic and kinetic parameters with and without presence of photocatalytic oxidation reaction are obtained to analyze arsenic removal capacity of the TiO2 nanoparticles

Enhanced photocatalytic oxidation of As3+ using titania nanoparticles for arsenic removal from water

Excessively high arsenic concentration in natural water and industrial wastewater is now a threatening problem for many countries especially Bangladesh, India, Germany, China and Turkey [1]. Titanium dioxide, a well-known adsorbent material, has been extensively tested for arsenic removal from water. However, arsenate ions (As5+) adsorbs more strongly onto the solid phase of adsorbent than arsenite ions (As3+). Therefore, the effectiveness of TiO2 nanoparticles in removing As3+ species from water have been enhanced by the photocatalytic oxidation in the presence of oxygen in ultraviolet (UV) light. In the present study, the photocatalytic oxidation of As3+ to As5+ is investigated in UV-illuminated TiO2. Batch adsorption experiment was carried out to analyze removal capacity of the TiO2 nanoparticles with and without presence of photocatalytic oxidation reaction and the adsorption isotherms were obtained. Keywords: Arsenic; Photocatalytic oxidation; Adsorption; Titanium dioxide nanoparticles [1] D. Mohan, C.U. Pittman Jr, Arsenic, Journal of Hazardous Materials , vol.142, 2007, 1–53

Combustion characteristics of Turkish hazelnut shell biomass, lignite coal and their respective blends via thermogravimetric analysis

Thermal behavior and combustion kinetic of coal, hazelnut shell, and coal/hazelnut shell blends at the proper ratio were investigated with thermogravimetric analysis (TG). Four mass ratios (20, 30, 40, 50 mass %) of coal/biomass blends were prepared and oxidized under dynamic conditions from temperature 298 to 1173 K at different heating rates. TG analysis indicated that the combustion of blended samples divided into two stages namely devolatilization and char oxidation combined with coal combustion step. The influence of biomass blends on thermal and kinetic behavior of coal was studied under non-isothermal conditions. It was found that the thermal degradation temperature of coal was higher than that of blended samples due to the molecular structure strength. Ozawa–Flynn–Wall model was applied to deal with non-isothermal TG data for the evaluation of the activation energy corresponding to the combustions of coal, hazelnut shell, and coal/hazelnut shell blends. The average activation energy changed in the range of 90.9–215.3 kJ mol-1, respectively, depending on blending ratio

Synthesis of mesoporous MCM-41 materials with low power microwave heating

Crystalline, high surface area, hexagonal mesoporous MCM-41 having uniform pore sizes and good thermal stability was successfully synthesized at 90-120oC in 30 minutes using low power microwave irradiation. This appears to be the first comprehensive and quantitative investigation of the comparatively rapid synthesis of mesoporous MCM-41 using low power microwave heating of 80W (90oC) and 120W (120oC). The influence of reaction temperature and the duration of heating were carefully investigated and the calcined MCM-41 materials were characterized by XRD, SEM, TEM, nitrogen adsorption, TGA and FTIR. The mesoporous MCM-41 product synthesized in 30 minutes at 120W and calcined at 550oC had a very high surface area of 1438 m2/g and was highly ordered, contained uniform pores with diameters in the range of 3.5-4.5 nm. The wall thickness of the materials highly depended on the power of the microwave energy used during the synthesis. Synthesis of the mesoporous MCM-41 products at 120oC resulted with a structure having thinner walls. The mesoporous MCM-41 materials synthesized in the present work had good thermal stability

Ergenlerde Olumsuz Kimlik Gelişiminin Önlenmesine Yönelik Aile Rehberlik Programı

Çalışmada, anne-babalara yönelik yapılandırılmış bir aile rehberliği programı ile gençlerde olumsuz kimlik oluşumu sonucu ortaya çıkabilecek problemler ve olası nedenleri konusunda bilgilendirici ve koruyucu bir çalışma yapılmıştır. Lise birinci ve ikinci sınıf öğrenci ebeveynlerine aile rehberliği programı uygulanmıştır. Program, anne-babalarla tek grup halinde yapılarak 6 haftalık bir aile rehberliği çalışmasından oluşmuştur. Programın içeriği temel alınarak araştırmacılar tarafından geliştirilen Bilgi Düzeyi Belirleme Ölçeği ve araştırmacılardan biri tarafından Türkçe’ye uyarlaması yapılan Anne-Babalık Becerileri ve İletişim Ölçeği ön-test ve son-test olarak kullanılmıştır. Ayrıca, açık uçlu sorulardan oluşan bir form ile katılımcılardan çalışmanın etkililiğini değerlendirmeleri istenmiştir. Anne-babaların ergenlik dönemi gelişim özellikleri ve etkili iletişim yöntemleri ile ilgili bilgi düzeylerinde bir artış gözlenmesine rağmen katılımcıların ergen çocuklarıyla iletişimlerinde tutum ve davranış düzeyinde bir farklılık bulunamamıştır