Showing 5 results for جنیدی جعفری
Somayeh Dehghani , Ahmad Jonidi Jafari, Mahdi Farzadkia, Mitra Gholami,
Volume 15, Issue 7 (December 2012)
Abstract
Background: Nowadays, international concern about the impact of antibiotic residues on the environment increased and their removal has received a lot of consideration. The aim of this study was to investigate the efficiency of Fenton’s advanced oxidation process (H2O2/Fe+2) in sulfadiazine antibiotic removal from aqueous solutions. Materials and Methods: An experimental-laboratory scale study was done on a synthetic wastewater containing sulfadiazine antibiotic with 0.079, 0.19, and 0.47 mM concentrations under Fenton’s process. Then optimal values of affecting parameters, such as initial antibiotic concentration, molar ratio of reagents, [Fe+2] and [H2O2] concentration, detention time, and pH, were determined. The discharged effluent analyzed by HPLC-UV to identify the antibiotic residues. Results: The results showed that the optimal parameters in the Fenton’s oxidation process to remove the sulfadiazine included antibiotics at pH 3.5, molar ratio of [H2O2] / [Fe +2] equal to 1.5, and contact time of 15 minutes, respectively. In these optimal conditions, the efficiency of removal of antibiotic in concentrations of 0.079, 0.19, and 0.47 mM were 99.82%, 97.97% and 78.23% and the wastewater COD removal degrees were 83.33%, 78.57%, and 78.57%, respectively. Conclusion: The experiments showed the efficient removal of sulfadiazine antibiotic in wastewater by Fenton’s oxidation process. The efficiency of this method can also be considered in eliminating other antibiotics resistant to biological treatment
Reza Tajik, Hasan Asilian Mohabadi, Ali Khavanin, Ahmad Joneidi Jafari, Ardalan Soleimanian,
Volume 15, Issue 8 (January 2013)
Abstract
Background: Poly chlorinated biphenyls (PBCs) are the group of organic chemical materials that have a great chemical stability. These compounds are hazardous pollutants which pose various occupational and environmental problems. This study was conducted to determine the effect of microwave rays, hydrogen peroxide, Tio2 catalyst, and ethanol on the decomposition of PBCs. Materials and Methods: In this experimental study, a vessel reactor (250ml volume)that was connected with a tube connector to thecondensor system was used. A microwave oven with a fixed frequency of 2450 MHZ was used to provide microwave irradiation and ray powers used at 540, 720 and 900w. pH and temperature of the samples were continuously monitored and the experiments were repeated three times. Askarel oils were analyzed by GC-ECD. Results: The mean of total PCBS degradation at 540, 720, and 900w was 83.88±1.63, 89.27±2.44, and 95.98±0.81%, respectively. The mean of total PCBS degradation in terms of ratio to solvent with oil transformer in 1:1, 2:1, and 3:1 was 53.8±3.26, 79.04±1.24, and 95.08±1.69%, respectively. The mean of total PCBS degradation in terms of not using H2o2/Tio2 and using H2O2 (20%) and 0.05, 0.1, 0.15, and 0.2 g of Tio2 concurrently was 71.47±0.81, 87.9±2.16, 89.48±1.69, 91.7±1.24, and 93.07±3.09 %, respectively. Conclusion: Using microwave irradiation in the presence of H2O2 oxidant and Tio2 catalyst leads to the reduction of PCBS.
Kazem Nadaffi, Ramin Nabizadeh, Ahmad Jonidi Jafari, Kamyar Yaghmaeian, Ali Koolivand,
Volume 16, Issue 12 (3-2014)
Abstract
Background: Remaining of crude oil in storage tanks usually lead to accumulation of oily sludge at the bottom of the tank which should be treated and disposed of in a suitable manner. In this research the feasibility of chemical oxidation with H2O2 and Fenton's reagent for removal of total petroleum hydrocarbons (TPH) from composted storage tank sludges was investigated.
Materials and Methods: The sludge was mixed with immature compost at various sludge to compost ratios including 1:2, 1:4, 1:6, 1:8 and 1:10 and composted for 82 days. Then, hydrogen peroxide and Fenton’s reagent were added to the composted mixture in six concentrations including 2%, 5%, 10%, 15%, 20% and 30% w w-1 for a period of 24 and 48 hr.
Results: TPH removal in composting reactors with the ratios of 1:2, 1:4, 1:6, 1:8 and 1:10 were 66.59, 73.19, 74.81, 80.20 and 79.91 percent, respectively. The mean TPH removal of 1:8 composted mixtures with 2%, 5%, 10%, 15%, 20% and 30% of oxidant concentrations were 1, 5.09, 19.37, 28.16, 34.37 and 38.05 percent, respectively. The highest removal efficiency was achieved in stepwise addition to the sludge. As well, increasing oxidation time from 24 to 48 hr had a little effect on TPH removal increase and the removal efficiencies of H2O2 and Fenton were nearly similar.
Conclusion: Chemical oxidation with hydrogen peroxide and Fenton as a post-treatment step is an acceptable process in TPH removal from bottom sludge of storage tanks.
Farzaneh Jajarmi, Ahmad Jonidi Jafari, Majid Kermani, Mitra Gholami,
Volume 22, Issue 1 (4-2019)
Abstract
Background and Aim: Dust was considered by researchers as one of the most important forms of air pollution. The aim of this study was to identify the physical and chemical characteristics of dust storm sources in Tehran.
Materials and methods: This study was conducted in selected air sampling stations of Tehran, in the days of dust and ordinary from January 2016 for one year. The concentration of dust particles was determined by gravimetric. Heavy metal concentrations in samples after digestion were determined with graphite furnace atomic absorption spectrometry (AAS-GF). Mineralogy and morphology of the dust fall particles were inspected using X-ray diffraction and scanning electron microscopy and sources particles using Enrichment Factor Analysis and principal component analysis (PCA) were performed. For statistical analysis, R software was used.
Ethical Considerations: This study with research ethics code IR.IUMS.REC.1397.313 has been approved by research ethics committee at Iran University of Medical Sciences.
Findngs: The highest average particle concentration in normal days was related to the central station (122.63 µg / m3), and the lowest for the East Station (67.13 µg / m3). The highest concentrations of the elements measured in the particles are related to iron and aluminum and the lowest concentrations of chromium and nickel. Lowest amount of Enrichment Factor was obtained for iron, less than one.
Conclusion: The results of this study indicated that the concentration of dust in center was higher than other station. Natural and human resources both play a significant role in the release of metals. By conducting further studies on the source of dust in Tehran and using the results, effective control measures can be designed and implemented.
Hamid Reza Joneidi Jafari, Parisa Nejati, Ahmad Nazari, Azar Moezy,
Volume 24, Issue 6 (February & March 2022)
Abstract
Background: Rotator cuff injuries are one of the most common causes of shoulder pain.
There are different therapeutic approaches in this disease. The evidence of the positive effect of exercise therapy in this pathology is inconclusive. This study aimed to investigate the effect of a complete exercise protocol on improvement of the patients with rotator cuff injuries.
Methods: The patients with shoulder pain received the 12-week exercise protocol in 4 phases if they had confirmed rotator cuff injuries in clinical examination and shoulder MRI.
Pain was measured by visual analog scale (VAS) and function was measured by two questionnaires; disabilities of the arm, shoulder and hand (DASH) and western Ontario rotator cuff index (WORC). Range of shoulder joint motion (ROM) was measured in five directions by goniometry. All of the outcomes were evaluated before intervention and in 6, 12, 24 weeks after starting the intervention.
Ethic: This study was registered in Iranian Registry of Clinical Trials (IRCT20100718004409N13). A written consent was taken from All participants before the study.
Results: In this study Twenty-four patients with rotator cuff tendinopathy and tear were analyzed finally in terms of effectiveness of exercise therapy. The average of their age was 51.7 years old. 14 patients (53.8%) with Supraspinatus tendinopathy, 6 patients (23%) with Supraspinatus tear, 3 patients (12.5%) with Supraspinatus plus biceps tendinopathy, and one patient (4.16%) with Subscapularis plus Biceps tendinopathy were assessed. The pain score (Visual Analog Scale) decreased at all fallow-ups specially after 24 weeks (3±0.1) versus before intervention (8±0.1) (P value < 0.001). Shoulder range of motions by goniometer and also the patients function based on WORC and DASH Questionnaires were improved after 24 weeks versus before intervention that was significant statistically and clinically (P value < 0.001).
Conclusion: A 12- week exercise protocol including strengthening, stretching, PNF and dynamic stabilizer exercises was effective on pain reduction and improvement of function and shoulder joint range of motion improvement in the patients with shoulder rotator cuff tendinopathy and partial tear. The improvement of the variables lasted 6 months.
