Study of PAN Fiber and Iron ore Adsorbents for Arsenic Removal

The main idea to conduct this study is the treatment of hazardous arsenite (As+3)  and arsenate (As+5)from water by two efficient adsorbetns i.e. polyacrylonitrile fiber (organic) and iron ore (inorganic). Polyacrylonitrile (PAN) fibers were chemically modified prior to loading iron using a solution of diethylenetriamine and aluminum chloride hexahydrate. The characterization of PAN fibers was performed through FTIR spectroscopy, which shows the binding of functional groups on PAN fibers surfaces. Atomic absorption spectrometer (AAS) was used to analyze arsenic concentration in samples. The impact of pH, dosage, shaking (contact) time and shaking speed was studied and parameters were optimized for further study. The highest adsorption of 98% is exhibited by modified PAN fiber for As+5 while for As+3 removal is 80%. Modified PAN also showed higher adsorption capacity of 42×103μg/g for As+5 which is better than the As+3 adsorption capacity 33×103 μg/g. Overall results demonstrated that MPAN adsorbent is better than the iron ore adsorbent for the treatment of both As+3 and As+5. Comparative studies of PAN Fiber and iron ore adsorbents revealed that PAN fibers had better adsorption properties than iron ore for As+3  and As+5 in terms of percentage removal and capacity

Spontaneous regression of a primary squamous cell lung cancer following biopsy: a case report

Background: Spontaneous regression has been defined as occurring when the malignant tumor mass partially or completely disappears without any treatment or as a result of a therapy considered inadequate to influence systemic neoplastic disease. Recently, studies have implicated immunological responses as likely being involved. We report a case of a patient with squamous cell carcinoma of the lung who experienced spontaneous regression following biopsy without other intervention. Case Presentation: A 57-year-old white man was referred to our pulmonary clinic after an incidental finding of a nodule in the lower lobe of his left lung. Thoracic computed tomography revealed a 2.0 × 1.4 × 1.5 cm spiculated nodule in the superior segment of the left lower lobe. Workup identified the mass as a squamous cell carcinoma that was clinically staged as T1M0N0. The patient deferred treatment of this lesion. He undertook no significant lifestyle or medical changes. Three months later, computed tomography revealed that, compared with the initial study, the solitary mass had decreased in size to 1.6 × 0.9 × 0.9 cm. Follow-up computed tomography 1 year after the original workup demonstrated that the nodule had stabilized to its smaller size. Conclusions: Studies have shown that immunological response can be initiated by trauma to an area. Because the tumor regression became evident in our patient only after the tissue biopsy, his immune response to the surgical procedure seems to be a plausible contributor to the spontaneous regression. Further understanding of spontaneous regression can potentially impact the identification of neoplastic drug targets or even the course of a patient\u27s treatment plan and goals

Hydrodynamics study of the modified rotating disc contactor for CO2 absorption from natural gas using emulsion liquid membrane

This study modified the rotating disc contactor (RDC) structure to optimize its performance for CO2 separation from natural gas feed using stable emulsion liquid membrane (ELM). Based on parametric study of absorption of CO2 from natural gas feed into ELM, the mass transfer behavior in the RDC system was optimized. Rotor diameter, stator inner diameter, and minimum free area of RDC were modified to achieve maximum contact between dispersed liquid phase and gas feed phase, which was necessary to achieve maximum mass transfer. The problem of rupture of the emulsion droplet due to pressure created by direct dispersion of gas at the bottom of conventional RDC extraction system was addressed by adding an impeller at the bottom compartment of RDC. The impeller provided continuous mixing of emulsion and a gas sparger was fitted along the impeller's side that maintained the dispersed aqueous phase miscible in system. The hydrodynamic behavior of a modified RDC was optimized for CO2 absorption from natural gas in ELM, which indicated that modified design dimensions can provide a maximum liquid-gas contact. Beside the concentration of CO2 in natural gas feed, it was observed that the speed of RDC and run time significantly influence CO2 absorption from natural gas using ELM. When all the parameters optimized for CO2 absorption from natural gas feed this study is useful in extending the application of RDC in liquid-gas system. In this study, the use of ELM in RDC can be effective for CO2 when applied under proper conditions

Efficient Removal of Chromium and Lead from Tanneries Effluent of Korangi Industrial Area Karachi Using Rotating Disk Mesh as Anode Electrode Electrocoagulation

The aim of this study was to examine the best electrode design for the electrocoagulation process with the best removal performance, reduced passivation on the electrode surface, and lower energy consumption requirements for removing Chromium (Cr) and Lead (Pb) from leather tannery effluent. Three different electrodes were compared: non-rotating disk electrode (NRDE), rotating disk electrode (RDE) and rotating disk mesh electrode (RDME). All electrodes were used to observe a reduction in passivation on the electrode surface and its effects on the removal performance of Cr and Pb. The material used for the electrodes was iron. The maximum removal efficiency obtained was Cr = 87.9% and Pb = 97.5% under the following operating conditions: pH = 7, treatment time = 90 min, current density = 6.57 mA/cm², and RPM = 80. The results show that the electrical energy requirement for treating chromium and lead using RDME was 4.5 kWh/m³, which was found to be lower than the energy requirement observed in various other studies for treating tannery effluent. According to the results, RDME shows the highest removal performance with lower specific energy consumption compared to NRDE and RDE. RDME can be efficiently employed at a larger scale for treating leather tannery effluent

Innovative method to prepare a stable emulsion liquid membrane for high CO2 absorption and its performance evaluation for a natural gas feed in a rotating disk contactor

This paper presents an innovative method to prepare a stable emulsion liquid membrane (ELM) for high CO2 absorption in a natural gas feed. This new method achieved high throughput at low power consumption. The ELM prepared using this new method was characterized by determining the effects of the concentration of the ELM constituents, emulsification time, and speed on the emulsion droplet size (EDS) and stability. This was followed by a parametric study of the process parameters for CO2 separation from natural gas in a rotating disk contactor (RDC)-based setup to evaluate the performance of a stable ELM. The results suggest that the retention time of the stable ELM in a RDC increases with increasing amount of absorbed CO2. The results support the fundamental development of the ELM process to achieve a high overall separation efficiency of CO2 removal from natural gas with a relatively small contact time. This is the first parametric study of CO2 absorption from a gas stream in ELM using a RDC as the contracting equipment. The results of the parametric study suggested that the factors of time, TEA concentration and RDC speed have significant effect on the CO2 absorption from natural gas feed. It was identified that 4% TEA in ELM, 30 min operational time and 700 rpm speed of modified RDC system is suitable for maximum CO2 absorption from gas mixture of CO2/CH4. Furthermore, the study suggested that the ELM containing 4% TEA can absorb 5.6 kmol/m3 CO2

Complete Genome Sequences of Mycobacterium smegmatis Phages NihilNomen and Carlyle, Isolated in Las Vegas, Nevada

We present the complete genomes of the Mycobacterium smegmatis phages Carlyle and NihilNomen, isolated from soil in Las Vegas, Nevada. The phages were isolated and annotated by undergraduate students enrolled in the Phage Discovery course offered by the School of Life Sciences at the University of Nevada Las Vegas

Polymeric membrane used in natural gas processing to separate carbon dioxide: the facing problems and solutions

For the last two decades polymeric membranes have been used in several gas separation processes. For the high selectivity and permeability various types of membranes have been developed. Thin layers to high dense and hollow fiber to asymmetric wounded materials to determine the effective separation of CO2 from CH4 were used. Ideal membrane materials must have provisions of durability, chemical and thermal resistance, effective separation and economical production and operation. In this review it is observed that most of the polymeric materials face plasticization problem in the separation of CO2 from CH4. This is due to the condensable nature of carbon dioxide that causes swelling in most of the polymeric membranes due to which the efficiency of selectivity and permeability is affected. Most extensive works have been carried out in developing the chemical structure and compositions of polymeric materials to improve the separation properties. Cross-linking and blending of molecular sieving called “mixed-matrix” are the most useful approaches applied in this regard, but no where it is found to be fully effective and ideal polymeric membranes commercially fit to replace the existing systems of CO2 separation from the natural gas. Still area is open to work on to produce more worth full materials and switch towards liquid membranes and hybrid systems

A Combined CFD-Response Surface Methodology Approach for Simulation and Optimization of Arsenic Removal in a Fixed Bed Adsorption Column

An experimentally validated CFD model was developed for lab-scale arsenic (As) fixed-bed columns using COMSOL Multiphysics. The effects of key factors such as the adsorbent bed depth, the feed flow rate, and the initial As concentration (conc.) on the overall As removal performance were investigated. Subsequently, the CFD was combined with response surface methodology (RSM) to optimize process conditions and examine main and interaction effects of these factors on model responses, i.e., the As removal efficiency and the bed saturation time. The ANOVA results suggested that quadratic regression models were highly significant for both responses. The established regression model equations predicted the response values closer to CFD measurements. It was found that, compared with the initial As conc. and the feed flow rate, the effect of the bed depth was more significant. Moreover, both the As removal efficiency and the bed saturation time were increased reasonably with the increasing bed depth and decreased with the increasing feed flow rate and initial As conc. The optimum conditions for the As removal process were obtained as the bed height of 80 cm, the initial As concentration of 2.7 mmol/m3, and the feed flow rate of 1 L/min. The present combined CFD−RSM approach is a useful guideline in overall design and optimization of various lab-scale and industrial applications for removal of As from wastewater