High-performance removal of toxic phenol by single-walled and multi-walled carbon nanotubes: Kinetics, adsorption, mechanism and optimization studies

Mohammad Hadi Dehghani,Masoome Mostofi,Mahmood Alimohammadi,Gordon McKay,Kaan Yetilmezsoy,Ahmad B. Albadarin,Behzad Heibati,Mohammad Al Ghouti,N.M. Mubarak,J.N. Sahu 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.35 No.-

The adsorption capabilities of two nano-sized adsorbents: multi-walled carbon nanotubes (MWCNTs)and single-walled carbon nanotubes (SWCNTs) were investigated for the removal of toxic phenol. Themaximum adsorption capacities of MWCNTs and SWCNTs were determined as 64.60 and 50.51 mg/g,respectively. Adsorption kinetics followed the pseudo-second order model for both adsorbents. Theoptimum conditions using SWCNTs and MWCNTs were pH 6.57 and 4.65, phenol concentration 50 and50 mg/L, dose 1.97 and 2 g/L and contact time 36 and 56 min, respectively. The results indicated thatMWCNTs and SWCNTs were proven as high-performance adsorbents for toxic phenol removal fromwastewater.

Optimization of fluoride adsorption onto natural and modified pumice using response surface methodology: Isotherm, kinetic and thermodynamic studies

Mohammad Hadi Dehghani,Maryam Faraji,Amir Mohammadi,Hossein Kamani 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.2

Natural pumice (NP), FeCl3·6H2O modified pumice (FEMP) and hexadecyl trimethyl ammonium bromide (HDTM.Br) modified pumice (HMP) were used for fluoride adsorption. The effect of pH (3-11), initial concentration (2-15mg/L), and adsorbent dosage (0.2-0.8 g/L) on the defluoridation was optimized by using central composite design (CCD) in the response surface methodology (RSM). Results showed optimum condition in the pH=3, initial concentration=2mg/L, and adsorbent dosage=0.71, 0.75, 0.70 g/L with the maximum removal efficiency of 9.39, 76.45, and 95.09% for NP, FEMP, and HMP, respectively. The adsorption equilibrium and kinetic data was in good agreement with Freundlich and pseudo-second order reaction. Thermodynamic parameters indicated a non-spontaneous nature for NP and spontaneous nature for FEMP and HMP. Positive enthalpy illustrated the endothermic nature of the process. On the basis of results, modification of pumice led to an increase in the fluoride removal efficiency.

Removing Reactive Red 120 and 196 using chitosan/zeolite composite from aqueous solutions: Kinetics, isotherms, and process optimization

Mohammad Hadi Dehghani,Aliakbar Dehghan,Aliasghar Najafpoor 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.51 No.-

A low-cost adsorptive composite was prepared using natural zeolite, clinoptilolite, and shrimp shellwastes as raw materials. The shrimp waste was used to synthesize chitosan by the deacetylation of chitinwhich was extracted from the exoskeleton of crustacean shrimps. Response surface methodology (RSM)was employed to model and optimize the effect of process variables including initial dye concentration(25–100 mg/L), solution pH (3–11), adsorbent dose (1–3 g/L), and contact time (15–180 min) on thepercentage of dye removal as the response. The optimum levels of independent variables for the removalof Reactive Red 120 (RR120) were time of 138.75 min, initial concentration of 43.79 mg/L, adsorbent doseof 2 g/L, and pH of 5. The optimum values for the removal of Reactive Red 196 (RR196) were time of125.77 min, initial concentration of 44.72 mg/L, adsorbent dose of 2.5 g/L, and pH of 5. Under optimalconditions, the predicted removal percent of the model was 91.2 and 100% for RR120 and RR196,respectively. The results showed that the experimental data of RR120 were better described by Hill andSips isotherms, and experimental data of RR196 followed Jovanovic isotherm model. The pseudo-firstorderand pseudo-second-order models were employed to analyze the kinetic data. The kinetic data werewell described by pseudo-second-order model with R2Adjvalues of higher than 0.98 and 0.99 forRR120 and RR196, respectively. The results showed that all of the independent variables exhibited asignificant effect on dye removal.

Response surface modeling, isotherm, thermodynamic and optimization study of arsenic (V) removal from aqueous solutions using modified bentonite-chitosan (MBC)

Mohammad Hadi Dehghani,Ahmad Zarei,Alireza Mesdaghinia,Ramin Nabizadeh,Mahmood Alimohammadi,Mojtaba Afsharnia 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.3

Arsenic contamination, a worldwide concern, has received a great deal of attention due to its toxicity and carcinogenicity. In the present study, we focused on the combined application of modified bentonite and chitosan (MBC) for the removal of As(V). Arsenic removal experiments were carried out to determine the amount of As(V) adsorbed as a function of pH (2-8), sorbent dosage (0.1-1.5 g/L), As(V) concentration (20-200mg/L) and time (60-240 min). The system was optimized by means of response surface methodology. The analysis of variance (ANOVA) of the quadratic model demonstrated that the model was highly significant (R2≈97.3%). Optimized values of pH, sorbent dosage, initial As(V) concentration and time were found to be 3.7, 1.40 g/L, 69mg/L, and 167min, respectively. The results reveal that the prepared adsorbent has a high adsorption capacity (122.23mg/g) for As(V) removal. Among the isotherm models used, the Langmuir isotherm model was the best fit for the obtained data. The adsorption kinetics following a pseudo-second-order kinetic model was involved in the adsorption process of As(V). Thermodynamic studies confirmed the spontaneous and endothermic character of adsorption process.

Removal of methylene blue dye from aqueous solutions by a new chitosan/zeolite composite from shrimp waste: Kinetic and equilibrium study

Mohammad Hadi Dehghani,Aliakbar Dehghan,Hossein Alidadi,Maryam Dolatabadi,Marjan Mehrabpour,Attilio Converti 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.6

The adsorption of methylene blue dye (MBD) from aqueous solutions was investigated using a new composite made up of shrimp waste chitosan and zeolite as adsorbent. Response surface methodology (RSM) was used to optimize the effects of process variables, such as contact time, pH, adsorbent dose and initial MBD concentration on dye removal. The results showed that optimum conditions for removal of MBD were adsorbent dose of 2.5 g/L and pH of 9.0, and initial MBD concentration of 43.75mg/L and contact time of 138.65 min. The initial concentration of dye had the greatest influence on MBD adsorption among other variables. The experimental data were well fitted by the pseudo-second order kinetic model, while the Freundlich isotherm model indicated a good ability for describing equilibrium data. According to this isotherm model, maximum adsorption capacity of the composite was 24.5mg/g. Desorption studies showed that the desorption process is favored at low pH under acidic conditions.

Esophageal, Gastric and Duodenal disorders : Migraine Headache And Peptic Ulcer Diseased In Children

( Mohammad Hadi Imanieh ),( Mahrnood Haghighat ),( Seved Mohsen Dehghani ),( Maziyar Irani ),( Maryam Yousefi ),( Davood Mehrabani ) 대한소화기학회 2007 SIDDS Vol.9 No.-

Background/Aims: Although correlation between migraine headache and GI symptoms were reported, they did not significantly support the correlation between migraine headache and mucosal inflammation or peptic ulcer diseases. This study aimed to find such a correlation. Methods: There were 70 patients (5-15 years old) who had endoscopic documented mucosal inflammation or peptic ulcer diseases. Frequency of migraine headache in this group and a group consisting of a sample of normal population (300) who had not any GI problem in the past year was determined by a questionnaire. Results: The mean age of patients was 10.34 years with male to female ratio of 4:3. Frequency of migraine headache, esophagitis, gastritis, gastric ulcer, duodenitis, and duodenal ulcer was 22.9%, 68.6%, 92.9%, 4.3%, 24.3% and 4.3%, respectively. Regarding frequency of migraine headache among the normal population which was 12.4%, the frequency of migraine headache among patients with mucosal inflammation and peptic ulcer diseases of the upper GI tract, which was 22.9% showed significant statistical correlation. A significant correlation was seen between migraine and esophagitis and also between migraine headache and gastritis. Conclusions: The presence of significant correlation between migraine headache and mucosal inflammation or peptic ulcer diseases of the upper GI tract supports some of precious studies suggested this correlation.

Disorders of Small and Large Intestine : Bowel Movement Patterns and Dietary Fiber Consumption in Pediatric Patients With Appendicitis In Shiraz, Southern Iran

( Mohammad Hadi Imanieh ),( Seyed Abbas Banani ),( Seyed Mohsen Dehghani ),( Rahim Khajeh ),( Issah Gakurya ),( Davood Mehrabani ) 대한소화기학회 2007 SIDDS Vol.9 No.-

Background/Aims: Acute appendicitis is one the most important causes of acute abdominal peritonitis emergency laparatomy. This study aimed to determine the bowel movement patterns and dietary fiber consumption in pediatric patients with appendicitis in Shiraz, southern Iran. Methods: The study included 202 pediatric patients under the age of 18 years at Nemazee Hospital affiliated to Shiraz University of Medical Sciences, who had undergone appendectomy with the preoperative diagnosis of acute appendicitis from March 2003 to March 2004. A written semi-standard questionnaire was used to record age, gender, stool consistency, number of bowel movements, type of bread consumed, habit of fruit and vegetable consumption, clinical presentation, the time taken from onset of symptoms to arrival in hospital, the interval between date of admission in the emergency room to the time of surgery, and the duration of postoperative hospitalization. The pathology of appendicitis was clarified and recorded. Results: The patients aged from 3-8 years (mean=11.2, SD=3.6 years), with the male to female ratio of 2:4. Anorexia was the most common symptom (78.7%). Of 31 patients with constipation, 58% did not report daily regular intake of fruits. Only 3 patients (9.7%) had regular daily consumption of vegetables, and 27 patients (87.1%) had pathology reports of fecalith, while in the non-constipated patients, only 1.2% had such reports. The abdominal pain was periumbilical in many patients (42.6%), which shifted to MeBurny point in most patients (96%). 134 patients (66.3%) visited a health center within 24 hours after the first symptoms. Surgeries were performed on 132 patients (65.3%) within 6 hours, on 67 patients (33%) within 6-12 hours, and on 3 patients (2%) in more than 12 hours. Conclusions: Our findings suggested a high rate of constipation in patients with lower fiber intake, which was consistent with the hypothesis indicating the role of dietary fibers in lowering the incidence of appendicitis.

Endoscopy and Imaging Modalities/Basic Science of Gastrointestinal Disorders/Miscellaneous : Endoscopic Findings In Children On Non-Steroidal Anti-Inflammatory Drugs (NSAIDS)

( Reza Amin ),( Mohammad Hadi Imanieh ),( Sara Kashef ),( Seyed Mohsen Dehghani ),( Kiumehr Batebi ),( Issah Gakurya ),( Davood Mehrabani ) 대한소화기학회 2007 SIDDS Vol.9 No.-

Background/Aims: Non-steroidal anti-inflammatory drugs (NSAIDs) remain as the initial approach to the pharmacologic management in juvenile rheumatoid arthritis (JRA). Gastrointestinal (GI) damage associated with NSAIDs is common in adults, but there are few studies available in children. This study was done to determine the GI complications of NSIDs in a cohort of JRA patients by endoscopy. Methods: Twenty-one patients with JRA who were using NSAIDs for at least 3 months were assessed clinically and by endoscopy. Results: The mean age of the patients was 9.8 years (11 female). GI symptoms were found in 42.9% of patients: 33.4% abdominal pain and 9.5% vomiting. Macroscopic endoscopic lesions were found in 85.7% and infection of Helicobacter pylori (Hp) in 14.3% of cases. Conclusions: Our data show that patients using NSAIDs have frequent GI damage without any relation to the duration of treatment. The number of children who had GI damage without any clinical complaint was high. Also we found that there is no significant relationship between the duration of drug use and the GI complaints, and no relation between duration and GI complaints to upper GI tract endoscopic lesions. The possibility of GI derangements with NSAIDs in pediatric age group is high. Close monitoring of symptoms and prevention measures is suggested.

Esophageal, Gastric and Duodenal Disorders : Esophageal Caustic Injuries and Colon Interposition in Children: Long-Term Follow-UP

( Hamid Reza Forutan ),( Mohammad Hadi Imanieh ),( Seyed Mohsen Dehghani ),( Reza Mostafavi ),( Farnaz Khademolhosseini ),( Davood Mehrabani ) 대한소화기학회 2007 SIDDS Vol.9 No.-

Background/Aims: As sodium hydroxide (NaOH) is frequently used as a cleaning agent for air conditioners in southern Iran, caustic esophageal injuries happen frequently especially in children. After undergoing several dilatation procedures of the esophagus, a number of these patients eventually require colon interposition, an operation by which the esophagus is replaced by a segment of colon. Colin interposition is a surgical treatment modality for patients with severe caustic injuries in the esophagus. This study describes the technique and results of colon interposition in patients who bad undergone this operation. Methods: All patients who underwent colon interposition in Nemazee Hospital affiliated to Shiraz University of Medicals. Sciences in southern Iran from April 1990 to April 2005, were enrolled in our study. Medical records of these patients were reviewed and they were called for a follow-up examination. Out of 18 patients, only eight patients responded. They underwent clinical examination, laboratory tests, imaging and endoscopy. Results: Growth retardation was seen in all cases. All radiographs of the chest revealed peribronchial thickening. Redundancy was seen in 60% of the patients. Lower junction stenosis, diverticulum and dilatation of the lower esophagus were commonly visible. Epigastric fullness (85%), dysphagia (57%), halitosis (45%), heartburn (45%), vomit-ting (45%), odynophaqgia (28%) and abdominal pain (28%) were the most common complications. They were no mortalities in our series. Conclusions: As growth retardation was the most common complication of colon interposition in children, an appropriate nutritional support seems to be necessary after the operation.