72 research outputs found
Feasibility study of recycling and converting acidic sludge to bitumen in used motor oil refining industries
Background and Aims: Thousand tons of acidic sludge is produced daily as by-product in the used motor oil refining industries. The acidic sludge contains unsaturated compounds which are non-polar and asphaltene. The objective of this study was performance improvement of acidic sludge by using the additives (bentonite, polymer SBS, sodium hydroxide and the lime) so that recovery to bitumen.Materials and Methods: The polymer styrene - butadiene - styrene (SBS) is bitumen modifier as one of the elastomer - thermoplastic with weight percentages (2 to 4 percent), bentonite due to the chemical structure as fillers, stabilizers and agent concentration with weight percentages (1,2,4,6,8,10) and lime and sodium hydroxide were used to decreasing acidity rate of acidic sludge and promoting the role of bentonite stability in bitumen with ratios equal (1 to 5 g) were mixed with acidic sludge of industry (samples 50 g) and their effect on the acidic sludge was investigated.Results: Evaluation of studies indicated that because of increasing acidic sludge softening point, temperature from 25 to 48 oC , decrease weight loss from 3% to 1.25, promoting the penetration degree to 230 mm, Frass breaking point to -7 and penetration index (PI) to the degree standard set (+1), the acidic sludge properties and performance were modified. The measurement of last three parameters was unavailable in primary sludge.Conclusion: Environmental and health hazards of acidic sludge will be decreases by treatment and neutralization. Also obtained products can be used in the building and road construction according to its specific bitumen criteria and characteristics.Key words: Recovery - Acidic sludge - Used motor oi
A novel method for recovery of acidic sludge of used-motor oil reprocessing industries to bitumen using bentonite and SBS
ABSTRACT
Acidic sludge is a by-product from used motor oil reprocessing industries, which thousand tons of this sludge are disposed into the environment as a hazardous waste material daily. The acidic sludge contains unsaturated compounds that are polar and asphaltene. The bitumen under certain conditions is produced from mixing of bentonite, polymer styrene – butadiene – styrene (SBS), and acidic sludge.
Context and purpose: The objective of this study was the recovery of acidic sludge to bitumen using additives such as bentonite and SBS. Also, the effect of additives with different weight percentages (wt%(on the performance parameters of bitumen was evaluated. At first, spilled oil was separated from the acidic sludge by a centrifugal concentrator. Then, concentrated acidic sludge and additives were mixed in together. Finally, the performance tests were carried out to compare the quality of acidic sludge with the obtained products.The results indicated that performance parameters such as softening point (SP), weight loss, penetration degree, PI, Frass breaking point, and temperature susceptibility (TS) were promoted from 37°C, 1.3%, 230 dmm, -0.07854, -5°C and 0.0451 to 54°C, 1%, 130 dmm, 2.7094, -11°C , 0.02721, respectively. According to the paired sample t-test analysis, a significant difference was found between the bentonite dosage and the improved performance parameters from concentrated acidic sludge and obtained products (pvalue ≤.001). The bentonite and SBS with 2 and 4 wt%, respectively were determined as the suitable additives in the recovery of acidic sludge to bitumen
Amoxicillin degradation with electro-persulfate combined with H2O2 from aqueous solution using response surface methodology
Background: Discharging wastewaters containing antibiotic into the environment causes some adverse
effects on the human health and other organisms. The present study investigated the efficiency of electropersulfate
combined with hydrogen peroxide (H2O2) process as a chemical oxidation in amoxicillin
(AMX) degradation.
Methods: Optimization of the significant operational independent variables was explored for removal
of AMX. Central composite design (CCD) was employed as a statistical tool for experimental design.
High-performance liquid chromatography (HPLC) was used for measuring AMX concentration. The
most effective factors of the electro-persulfate and H2O2 on the removal efficiency of AMX such as initial
concentration of AMX, initial pH, PS/H2O2 molar ratio, and the current density were measured.
Results: The optimum conditions for electro-persulfate removal efficiency of AMX to reach the
degradation efficiency of higher than 95.28 ± 2.64% at reaction time of 60 minutes were obtained at pH
= 4.23, AMX concentration = 31.9 mmol/L, current density = 39 mA/cm2, and PS/H2O2 molar ratio =
0.82. AMX degradation was satisfactorily predicted by the quadratic model with high possibility and
confidence level of 95%. The quadratic model had high regression coefficients (R2 = 0.9964 and R2
adj =
0.9926), which was totally acceptable. The removal efficiency of AMX reduced from 87.3 ± 6.1 to 25.9 ±
9 as pH increased from 5.5 to 7.
Conclusion: According to the results, the electro-persulfate and H2O2 process can be suggested as the
most effective, high efficient, and in-situ chemical oxidation for degradation of AMX.
Keywords: Amoxicillin, Hydrogen peroxide, Oxidation-reduction, Antibioti
Investigation of MPTMS-modified magnetic nanoparticles in the removal of lead and cadmium ions from aqueous solution: equilibrium and kinetic studies
زمینه و اهداف: در سالهای اخیر، مساله آلودگی محیطهای آبی با فلزات سنگین بسیار مورد توجه محققان قرار گرفته است. بدین منظور، مطالعه حاضر با هدف کارایی نانوذرات مغناطیسی اکسید آهن اصلاح شده با 3- مرکاپتوپروپیل تری متوکسی سیلان در حذف یونهای فلزی سرب و کادمیوم را از محیط آبی انجام گرفت.
مواد و روشها: در مطالعه حاضر نانوذرات مغناطیسی Fe3O4@SiO2-SH به روش ساده همرسوبی در دمای 80 درجه سلسیوس سنتز شد و سپس ساختار و مورفولوژی آن با استفاده از دستگاههای XRD، FT-IR، SEMو TEM مورد شناسایی قرار گرفت. در نهایت آزمایشات جذب بر روی محلول آبی انجام گرفت. در کلیه مراحل انجام پژوهش، موازین اخلاقی، مراعات گردید.
یافتهها: طبق نتایج، نانوذرات Fe3O4@SiO2-SH دارای توزیع یکنواخت با هسته کروی Fe3O4 و پوسته SiO2 میباشد که توسط لیگاندهای تیول اصلاح شده است. همچنین اثر پارامترهایی نظیر pH، دوز جاذب و مدت زمان تماس بر درصد حذف یونهای فلزی مورد بررسی قرار گرفت. نتایج تحقیق نشان داد pH معادل با 5 و 6 به ترتیب برای سرب و کادمیوم، زمان تماس 40 دقیقه و دوز جاذبg/L 0/8 شرایط بهینه مناسب جهت حذف یونهای فلزی از محلول است. معادلات کینتیک و ایزوترم بر این نکته تاکید داشت که روند جذب دو یون فلزی از مدل کینتیک شبه درجه دوم (0/98<R2) و ایزوترم دمایی لانگمویر (0/98<R2) تبعیت میکند.
نتیجهگیری: با توجه به نتایج حاصل، نانو ذرات سنتز شده Fe3O4@SiO2-SH تحت شرایط بهینه میتواند كارايي مناسبي در حذف یونهای فلزی سرب و کادمیوم از محلولهای آبی داشته باشد.Background and Aims: Environmental pollution by heavy metals has received much attention in recent years. Therefore, this study aims to remove lead and cadmium ions by using silica-coated magnetic nanoparticles modified with mercaptopropyltrimethoxysilane (MPTMS) from aqueous solutions.Materials and methods: In this study, Fe3O4@SiO2-SH magnetic nanoparticles were synthesized via the simplified co-precipitation method at 80°C. The structure and morphology properties of synthesized nanoparticles were characterized by XRD, FT-IR, SEM and TEM. Finally, the adsorption experiments were performed in aqueous media. All stages of this research were conducted ethically.Results: According to the results, Fe3O4@SiO2-SH nanoparticles have a uniform distribution with a spherical Fe3O4 core and SiO2 shell, modified by thiol functional groups. The efficiency of synthesized adsorbent in the removal of metal ions was also investigated considering parameters such as pH, adsorbent dose and contact time. The optimum conditions for lead and cadmium removal were obtained at pH 5 to 6, contact time 40 min and absorbent dose 0.8 g/L. The kinetic and isotherm studies underlined that the process of adsorption of both metal ions follows the second-order (R2> 0.98) and Langmuir isotherm (R2>0.98) models.Conclusion: Based on the results obtained, synthesized Fe3O4@SiO2-SH magnetic nanoparticles can present proper efficiency in the removal of lead and cadmium ions from aqueous media under optimum conditions
Photochemical of Polychlorinated biphenyl by the photolysis and solvent
Polychlorinated biphenyls (PCBs) are one group of persistent organic pollutants (POPs) that are of international concern because of global distribution, persistence, and toxicity. Removal of these compounds from the environment remains a very difficult challenge because the compounds are highly hydrophobic and have very low solubility in water. The photochemical reactor was of annular geometry with a cylindrical low-pressure mercury lamp. The whole Lamp was immersed in a reactor thermostat controlling the temperature at 32 ± 2 °C. The Polychlorinated biphenyls (PCBs) were analyzed by GC/ECD. The degradation of PCBs in terms of one, two and three lamp was 91.9%, 92.7% and 93% respectively. The degradation of PCBs in terms of use of 10% and 20% of total volume of solution of H2O2 were 88.8% and 93% respectively. The degradation of PCBs in terms of ratio to ethanol with oil transformer in 1:1, 2:1 and 3:1 was 83.4%, 92.5% and 93% respectively. The experiments show that UVC-photolysis of H2O2 leads to a degradation efficiency of PCBs in the presence of ethanol. @ JASEMJ. Appl. Sci. Environ. Manage. December, 2010, Vol. 14 (4) 107 - 11
Influence of pollution loading and flow rate on catalytic BTEX removal with a combined Cu2O, Fe0/Zeolite bed
ABSTRACT
Environmental impacts and health concerns of BTEX compounds have been pointed in many studies. The agencies responsible for health and environment have delivered standard and guideline for BTEX concentrations. Because of the extensive use in industries and the presence of these compounds in fossil fuels, their emission resources are very divers. Today's, Control of air pollution caused by these compounds is one of the air qualities controlling challenges. "Thermal catalyzed" process is one of the technologies to control this kind of air pollution and consistent with using nanoparticles as a catalyst, this process is further considered now. So, we conducted this study to survey elimination of the BTEX, form polluted air flow, by this process. In this study, removal of the BTEX from polluted air by a thermal catalyzed process in the presence of zero-valent iron and copper oxide nanoparticles was investigated and the effect of changes in pollution load and flow rate was surveyed on removal efficiency and the decomposition of the pollutants. Fe0 and Cu2O nanoparticles were coated on a bed of natural zeolite (Clinoptilolite) with a zeolite grains size of 1-2 mm. The thermal catalyst process was conducted at 350°C and different pollution loading and air flow rate. 96.18% and 78.42% of removal efficiency achieved with the retention times of 14.1s and 7.05s. Increasing the pollution load reduced removal efficiency and pollutants' mineralization. By doubling the pollution load, the removal efficiency declined as much as 14.5 %. According to the results, increasing of the flow rate has a greater effect than the pollution load on the complete decomposition. Also this process showed a good efficiency for BTEX removal under high pollution loading and flow rates
Development of a novel setup for direct colorimetric visualization of elemental mercury vapor adsorption on colloidal gold nanoparticles
ABSTRACT
Mercury is a toxic, persistent, and bio-accumulative pollutant that has adverse effects on environmental and human health. Various studies have been conducted to monitor different forms of mercury. The objective of this study was to develop a novel setup for assessing gas phase elemental mercury vapor adsorption using colloidal gold nanoparticles solutions that display a characteristic surface plasmon resonance absorption peak in the visible spectrum. The UV-VIS-NIR spectrographs of gold nanoparticles blue shifts after exposure to mercury vapor. The surface plasmon resonances (SPR) of ∼4 and ∼30 nm gold nanoparticles were appeared with the sharp peaks at 515 and 528 nm respectively. The mercury vapor adsorbed in gold nanoparticles was related to the size. The amounts of mercury vapor adsorbed per grams of ∼4 and ∼30 nm gold nanoparticles solutions were obtained 1100 µg•g-1 and 1300 µg•g-1 respectively. A proposed novel setup based on UV-Vis spectroscopic undertaken to provide simplicity, use facilitating, potentially inexpensive, and sensitive enough is a suitable system for mercury vapor capture in many fields. It was demonstrated that the amount mercury adsorbed has been related to the sizes of gold nanoparticles. The color change was observed, when elemental mercury vapor adsorbed on the gold nanoparticles
Study On The Acoustic Characteristics Of Natural Date Palm Fibres: Experimental And Theoretical Approaches
The present study deals with the acoustic performance of natural fibres originated from the date palm empty fruit (DPEFB) fibres which is mainly considered as agricultural waste. The fibres were processed and fabricated to be sound absorber samples with two different densities of 100 kg/m3 and 200 kg/m3 and with thicknesses of 10–40 mm. The normal incidence absorption coefficients of the sound absorbers were measured using an impedance tube based on ISO 10534-2. The effects of fibre density and sample thickness are discussed. The findings reveal that for density of 100 kg/m3 the absorption coefficient is 0.6–0.8 above 1.5 kHz for the samples with the thickness of 20 mm and 30 mm. For the thickness of 40 mm, the values even reached the value of 0.9. The values can reach 0.7–0.8 above 1 kHz for the density of 200 kg/m3. Mathematical model using the optimized Delaney-Bazley model with Nelder-Mead simplex method is shown to successfully predict the sound absorption coefficient of the fibre samples. The Johnson-Champoux-Allard model follows the trend of the absorption coefficient, but underestimates the measured data at high frequencies above 2.5 kHz
Evaluation of Chronic Obstructive Pulmonary Disease Attributed to Atmospheric O3, NO2 and SO2 in Tehran City, from 2005 to 2014
Air pollution in Tehran is considered as one of the most important factors threatening human health. High concentrations of pollutants have adverse effects on citizens and the environment. We calculated the relation between COPD and criteria air pollutants in Tehran, one of the most polluted cities in the world during 2005 to 2014.
Hourly data of pollutants include SO2, O3 and NO2 were taken from the Tehran environmental protection agency and Air Quality Control Company. The AirQ2,2,3 model that proposed by the WHO, is used to health impact assessment of pollutants in terms of hospital admission due to Chronic Obstructive Pulmonary Disease.
Results indicated that the total cumulative number of cases due to hospital admission due to COPD in Tehran city from 2005 to 2014 for SO2, O3 and NO2 was 1806, 2941 and 2454 cases, respectively. The finding of this study showed that total mean of SO2, O3 and NO2 was higher than the standard concentration. By comparison with guideline and standards, annual concentration for SO2, O3 and NO2 was exceeded on standard level in during the study period.
This study demonstrated that a high percentage of hospital admission due to Chronic Obstructive Pulmonary Disease resulting from these pollutants could be due to the high average concentration in the air of Tehran during 2005 to 2014. So, authorities must apply the efforts and necessities actions based on comprehensive scientific researches to control air pollutants and abate their negative effects on human health
Simultaneous Photo-Oxidative Degradation of EDTA and Extro-Oxidative Recovery of Copper from Industrial Effluents
ABSTRACT: The objectives of this investigation are the studies on the effect of copper ion o
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