Mohammad Abul Hossain

Adsorption kinetics of Rhodamine-B on used black tea leaves

Rhodamine B (Rh-B) is one of the most common pollutants in the effluents of textile industries effluents in developing countries. This study was carried out to evaluate the applicability of used black tea leaves (UBTL) for the adsorptive removal of Rh-B from aqueous system by investigating the adsorption kinetics in batch process. The effects of concentration and temperature on adsorption kinetics were examined. First-, second- and pseudo-second order kinetic equations were used to investigate the adsorption mechanism. The adsorption of Rh-B on UBTL followed pseudo-second order kinetics. The equilibrium amount adsorbed and the equilibrium concentration were calculated from pseudo-second-order kinetic plots for different initial concentrations of Rh-B to construct the adsorption isotherm. The adsorption isotherm was well expressed by Langmuir equation. The maximum adsorption capacity of UBTL to Rh-B was found to be 53.2 mg/g at pH = 2.0. The equilibrium amount adsorbed, calculated from pseudo-second-order kinetic plots, increased with temperature increase. The positive value of enthalpy of adsorption, ΔHads = 31.22 kJ/mol, suggested that the adsorption of Rh-B on UBTL at pH = 2.0 is an endothermic process.

Structural, mechanical, and electrical properties of carbon nanoparticles synthesized from diesel

abstract We studied the elemental analysis, structural morphology, mechanical, and electrical properties of carbon nanoparticles synthesized from diesel. The spherical carbon particle size in the range of about 10 to 80 nm in diameter was observed in scanning electron microscope (SEM) studies that were identified by Atomic force microscopy (AFM) study as an aggregation of carbon particles of average size 2.5 nm. The surface rms of carbon nanoparticle thin film (CNTF) was measured directly by AFM and found 0.22 nm. The Derjaguin–Muller–Toporov (DMT) elastic modulus of carbon nanoparticles (CNPs) was measured by PeakForce QNM mode of AFM. The minimum and maximum elastic modulus was measured of 0.40 GPa and 43.89 GPa, respectively. The resistivity, conductivity, magneto resistance, mobility, and average Hall co-efficient were measured by “Ecopia Hall-effect measurement system” by four-point Van der Pauw approach at ambient condition. We demonstrated I–V characteristic at the Indium/CNTF thin film interface, which is accompanied by rectifying behavior.

Comparative Adsorption of Methylene Blue on Different Low Cost Adsorbents by Continuous Column Process

Dyes are commonly found in the effluents of many industries. The effectiveness of adsorption for the removal of dye from wastewaters has been made it an ideal alternative to other expensive treatment methods. Continuous column adsorption is more affective than batch adsorption. A comparative column adsorption study was performed using three different low cost adsorbents for the removal of methylene blue from synthetic wastewater. Sand was collected from Cox’s Bazar, and sugarcane bagasse and used black tea leaves were locally prepared in laboratory. Three columns were designed for different adsorbents maintaining all conditions were to be approximately similar. UV-vis spectroscopic method was used for analysis of methylene blue in solution. Column adsorption experiments were performed to investigate the comparison of breakthrough curves and exhaust capacity of three different adsorbents. Column study shows that the adsorption capacity of used black tea leaves is highest. The adsorption capacity of bagasse is lower than tea leaves but higher than sand. Introduction There is an ever-increasing demand of fabrics and food in the whole world for the rapid expanding population. The wastewaters discharged from dying and printing processes contain high amounts of dissolved colored materials [1]. The disposal of colored wastes such as dyes and pigments into receiving waters damages the environment, as they are carcinogenic and toxic to humans and aquatic life [2, 3]. Besides the problem of color, some dyes impart non-visibility and can be modified biologically to toxic or carcinogenic compounds. Now a day’s concern has increased about the long-term toxic effect of water containing these dissolved pollutants. Methylene blue is commonly used in textile and printing industries. It is moderately to highly toxic by oral and intravenous routes. Eye contact can cause staining of the eye. Inhalations may cause dryness of mouth, flushed skin, rapid pulse, blurred vision, dizziness, etc. [4]. Therefore, proper treatment of wastewater containing methylene blue is essential before its discharge in aquatic system. Different methods are available for the removal of dyes like methylene blue from wastewater but most of them are expensive. Adsorption has received considerable attention for color removal from wastewaters as it offers the most economical and effective treatment methods. Due to high cost of activated carbon, adsorption on natural materials such as sand [5-7], saw dust [8-11], rice husk [10-11], used tea leaves [13-14], coconut coir [15], bagasse [16-17], banana pith [11], fly ash [10-11], orange peel [18] and modified biomaterials [19-21] have received considerable interest because of their local availability and their practically low cost. Use of above biomass materials [821] in batch adsorption process has been found to be highly effective, cheap and eco-friendly. But their proper process of application is very important. This study investigates the potential use of some low cost adsorbents for the removal of methylene blue using column method as a model test. The aim of the study was to compare the adsorption capacity of different low cost adsorbents such as sand, sugarcan bagasse and used black tea leaves, in column adsorption process by constructing breakthrough curves for different column materials using ideal operational conditions and determining their column exhaustive capacity. International Letters of Chemistry, Physics and Astronomy Submitted: 2017-04-04 ISSN: 2299-3843, Vol. 77, pp 26-34 Revised: 2017-12-20 doi:10.18052/www.scipress.com/ILCPA.77.26 Accepted: 2018-01-19 2018 SciPress Ltd, Switzerland Online: 2018-01-25 SciPress applies the CC-BY 4.0 license to works we publish: https://creativecommons.org/licenses/by/4.0/ Materials and Methods Preparation of adsorbent Sand. Sand is cheap and easily available in nature. In this study the sand was collected from Cox’s Bazar, Bangladesh. Figure 1(a) shows the optical view of the collected sand. It was dried well in an oven (NDO-450, EYELA, Japan) at 105 C for 4 hours, crushed and sieved through metallic sieve of mesh size 0.140 mm and screened out. Sugarcane baggase. Sugarcane bagasse (or bagasse) was collected from local market of Dhaka city and washed with boil water to remove the sweet materials. Then it was dried in an oven (NDO-450, EYELA, Japan) at 105 C for 5 hours, crushed and sieved through metallic sieve of mesh size 0.140 mm and screened out. Figure 1(b) shows the optical view of the collected bagasse. Used black tea leaves. Fresh black tea leaves were collected from departmental store in Dhaka city, Bangladesh. Figure 1(c) shows the optical view of the collected Fresh black tea leaves. About 50 g of fresh black tea leaves were boiled in 500 mL of distilled water for 2 hours. Boiled tea leaves were washed 3-4 times with hot distilled water followed by cold distilled water in several times until the tea liquor was completely disappeared. After washing, tea leaves were dried in an oven (NDO-450, EYELA, Japan) at 105 C for 10 hours. Dried used black tea leaves (UBTL) were sieved through the metallic sieve of mesh size 0.140 mm and screened out. Figure 1. Raw materials of adsorbants: (a) sand, (b) sugarcane bagasse and (c) Fresh black tea leaves. Methylene blue and its analysis Methylene blue (MB) is a heterocyclic aromatic compound, also known as methylthioninium chloride. It’s IUPAC name is 3,7-bis(Dimethylamino)-phenothiazin-5-ium chloride, CAS number is 61-73-4, molecular formula C16H18ClN3S and molar mass is 319.85 g∙mol. Synonyms of Methylene blue are Basic blue 9, Swiss blue, Chromosmon, Methylthionine chloride and Urolene blue. Methylene blue is a compound consisting of dark green crystals or crystalline powder, having a bronze-like luster. Solutions in water or alcohol have a deep blue color. Methylene blue is a potent cationic and basic dye with maximum absorption of light around 670 nm. The specificity of absorption depends on a number of factors, including protonation, adsorption to other materials, and metachromasy the formation of dimers and higher-order aggregates depending on concentration and other interactions [22]. Methylene blue can exist as MB, MBH2, (MB)2 and (MB)3 in aqueous solution. Three different forms of structural formula of methylene blue are presented in Fig. 2 [22]. Analytical grade Methylene blue (MB) was collected from Merck Germany. Required amount of dried methylene blue was taken to prepare 10×10 M of stock solution by dissolved in distilled water. Further dilution was made whenever necessary. To construct a calibration curve, the absorbance of different concentrated solutions of MB within the range of 1.0×10 to 4.0×10 M was measured at pH 6.5 by a double beam UV-vis spectrophotometer (UV-160A, Shimadzu, Japan) using λmax = 665 nm. Measured absorbance was plotted against the respective concentration of MB in different solutions to receive the calibration curve. (a) (b) (c) International Letters of Chemistry, Physics and Astronomy Vol. 77 27

Graphene oxide/carbon nanoparticle thin film based IR detector: Surface properties and device characterization

This work deals with the synthesis, characterization, and application of carbon nanoparticles (CNP) adorned graphene oxide (GO) nanocomposite materials. Here we mainly focus on an emerging topic in modern research field presenting GO-CNP nanocomposite as a infrared (IR) radiation detector device. GO-CNP thin film devices were fabricated from liquid phase at ambient condition where no modifying treatments were necessary. It works with no cooling treatment and also for stationary objects. A sharp response of human body IR radiation was detected with time constants of 3 and 36 sec and radiation responsivity was 3 mAW−1. The current also rises for quite a long time before saturation. This work discusses state-of-the-art material developing technique based on near-infrared photon absorption and their use in field deployable instrument for real-world applications. GO-CNP-based thin solid composite films also offer its potentiality to be utilized as p-type absorber material in thin film solar cell, as well.