Lima Rose Miranda

Modelling, analysis and optimization of adsorption parameters for H3PO4 activated rubber wood sawdust using response surface methodology (RSM)

Adsorption capacity of Cu(2+) from aqueous solution onto H(3)PO(4) activated carbon using rubber wood sawdust (RSAC) was investigated in a batch system. Kinetic and isotherm studies were carried out, the thermodynamic parameters like standard Gibbs free energy (Delta G degrees), enthalpy (Delta H degrees) and entropy (DeltaS degrees) were evaluated. The pseudo-second-order model was found to explain the kinetics of Cu(2+) adsorption most effectively. The process optimization was performed through Central Composite Rotary Design using response surface methodology (RSM) by Design Expert Version 5.0.7 (STAT-EASE Inc., Minneapolis, USA). An initial concentration of 35 mg L(-1), temperature of 26 degrees C, carbon loading of 0.45 g(100mL)(-1), adsorption time 208 min and pH of 6.5 was found to be the optimum conditions for the maximum uptake of copper ions of 5.6 mg g(-1) in batch mode.

Removal and recovery of Ni and Zn from aqueous solution using activated carbon from Hevea brasiliensis: batch and column studies.

In the present study, the adsorption behavior of Ni and Zn from aqueous systems onto activated carbon prepared from Hevea brasiliensis sawdust has been attempted via batch and column mode studies under various operating conditions. The experimental data were fitted to various isotherm models. The maximum adsorption capacity of Ni and Zn were found to be 17.21 and 22.03 mg g(-1), respectively, at 30 degrees C according to Langmuir model. Kinetic studies showed the adsorption process followed pseudo second-order rate model. Breakthrough curves were plotted for the adsorption of metal ions using continuous-flow column operation by varying the bed height, flow rate, initial metal ion concentration and temperature. At the end, an attempt has also been made to model the data generated from column studies using the empirical relationship based on Adam-Boharts model and Thomas model. The model constants were also evaluated. This has helped in ascertaining the practical applicability of the adsorbent. The column regeneration studies were carried out for three adsorption-desorption cycles. The elutant used for the regeneration of the adsorbent was 0.1 M H2SO4. On the basis of the results, ACHB can be economically and effectively used as an adsorbent for the removal of metal ions from wastewaters.

Electrochemical degradation of specialty chemical industry effluent

Conventional wastewater treatment techniques are inefficient to manage large quantities of refractory organics discharged by specialty chemical industries. It is aimed in the present investigation to compare overall performance of the basic electrochemical reactor configurations such as batch, batch recirculation and continuous recycle reactors, in removing the organic part of wastewater from a medium-scale, specialty chemical industry. The effects of current density, supporting electrolyte concentration, electrolysis duration and fluid flow rate on the pollutant removal and energy consumption performances were critically evaluated. Continuous recycle reactor is found to be the better configuration, because of its flexibility of operation. Circulation flow rate and withdrawal flow rate enable control on transfer coefficients and treatment duration respectively. The ability of artificial neural network (ANN) in predicting the performance of the batch electrochemical treatment has also been demonstrated.

Synthesis and Characterization of Cerium Doped Titanium Catalyst for the Degradation of Nitrobenzene Using Visible Light

Cerium doped catalyst was synthesized using Titanium isopropoxide as the Titanium source. The metal doped nanoparticles semiconductor catalyst was prepared by sol-sol method with the sol of Cerium. The synthesized catalyst samples were characterized by powder X-ray diffraction, BET surface area, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and UV-vis diffuse reflectance measurements (DRS) and compared with undoped TiO2 catalyst. The photocatalytic activity of the sample was investigated for the decomposition of nitrobenzene (NB) using visible light as the artificial light source. Cerium doped catalyst was found to have better degradation of nitrobenzene owing to its shift in the band gap from UV to visible region as compared to undoped TiO2 catalyst. The operational parameters were optimized with catalyst dosage of 0.1 g L−1, pH of 9, and light intensity of 500 W. The degradation mechanism followed the Langmuir Hinshelwood kinetic model with the rate constant depending nonlinearly on the operational parameters as given by the relationship (theoretical) = 2.29 * 10−4 * Intensity0.584 * Concentration−0.230 * Dosage0.425 * pH0.336.

Biodiesel production from mutton tallow

Presently the worlds energy needs are met through non-renewable resources such as petrochemicals, natural gas and coal, with the exception of Hydroelectricity and nuclear energy. Diesel fuels have the essential function in the industrial economy of a developing country and are used for transport of agricultural and industrial goods. The high energy demand in the industrial world as well as in the domestic sector and pollution problems caused due to the widespread use of fossil fuel make it necessary to develop the alternate energy from renewable sources with lesser environmental impact than traditional one. Thus, an alternate energy must be from a fuel which must be technically feasible, economically competitive, environmentally acceptable and readily available. One possible alternative is the use of oils of plant origin, which is termed as Biodiesel. It is a biodegradable, non-toxic, domestic resource thereby relieving reliance on petroleum fuel imports. It also has more favorable combustion emission profile, such as low emission of CO, particulate matter and unburned Hydrocarbon. CO2 produced by combustion of Biodiesel can be recycled by photosynthesis, thereby minimizing the impact of Biodiesel combustion on the green house effect. Though the heating value of Vegetable oil is similar to that of diesel fuel, their use in Direct Injection diesel engine is restricted by the physical properties like viscosity which is approximately 10 times higher than diesel fuel thereby creating poor fuel atomization, incomplete combustion, carbon deposition on the injector, fuel buildup in the lubricant oils resulting in serious engine fouling. These problems may be alleviated by employing various treatments like dilution with a suitable solvent, emulsification, pyrolysis and Transesterification. Transesterification is a common well established chemical reaction in which linear monohydroxyl alcohols reacts with vegetable oils which are triglycerides of fatty acids, in the presence of a catalyst. It is actually the replacement of alcohol group from an ester by another alcohol. Alkali catalyzed transesterification is considered to be the best amongst all methods available for the production of biodiesel from fresh oil. In the present investigation an attempt has been made to use mutton fat as low cost sustainable potential feed stock for biodiesel production. Effect of various process parameters such as amount of catalyst, temperature, amount of methanol and reaction time on biodiesel production was investigated. The optimal conditions for processing 50 g of mutton fat were obtained. Under optimal conditions, the yield of mutton fat methyl esters was 93.2%. The fuel properties like Density, kinematic viscosity, acid value, cloud point, iodine value, saponification value, pour point and cetane value was estimated. Mutton fat was found to be highly suitable to produce biodiesel with recommend fuel properties.

Agave sisalana, a biosorbent for the adsorption of Reactive Red 120 from aqueous solution

The textile industry is one of the largest producers of dye effluent. Treatment of these effluents has to be cost effective hence a number of precursors have been studied as a viable alternative adsorbent. Sisal fibre was converted to activated carbon by chemical methods. Sisal fibre was activated with different activating agents such as H3PO4, HCl, HNO3, NaOH and KOH. The adsorption of Reactive Red 120 (RR 120) dye onto sisal fibre activated carbon (SFAC) from aqueous solution was investigated. Adsorption experiments were carried out at different dye concentrations, initial solution pH and carbon dosage. Batch adsorption studies were carried out using activated carbon produced using phosphoric acid yielded better carbon as it good results in terms of Methylene Blue number and Iodine number. These carbons were used to study the batch adsorption studies. Methylene Blue number and Iodine number of SFAC were found to be 240 mg/g and 855 mg/g, respectively. The BET surface area of the carbon was 885 m2/g. The batch experiments adsorption isotherm studies fitted well to Langmuir isotherm and the adsorption capacity was found to be 110 mg/g. Adsorption kinetics data were tested using pseudo-first-order and pseudo-second-order models. Kinetic studies showed that the adsorption data followed a pseudo-second-order reaction.

Optimization of Activated Carbon Preparation from Pomegranate Peel (Punica granatum Peel) Using RSM

This research involves the optimization of different variables of the operating conditions to prepare activated carbon from pomegranate peels (Punica granatum peel). For this purpose, a statistical method called Response Surface Methodology (RSM) has been adopted to economize the number of experiments and their meaningful interpretation. Activated carbon was produced by chemical activation (H3PO4). RSM was used to evaluate the variables considered in the preparation of activated carbon such as impregnation ratio (2–4 g H3PO4/g pomegranate peel), temperature (400–600°C), and activation time (30–90 min), experimented using a three-variable Box–Behnken Design (BBD) based on a quadratic model and an RSM tool provided by Design Expert 8.0.4 (STAT-EASE Inc., Minneapolis, USA). The responses analyzed for optimization were the methylene blue number and the iodine number. The factors that are significant influencing the activated carbon preparation have been identified by an analysis of variance (ANOVA). The optimum conditions established were impregnation ratio of 2.78, activation temperature of 575°C, and activation time of 73 min.

Two-regime kinetic study and parameter optimization of degradation of 3,4-dichloroaniline using TI–N/S catalyst under visible light

AbstractThis paper presents the research of the effects of operating parameters on the photocatalytic degradation of 3,4-dichloroaniline (3,4-DCA) using non-metal doped TiO2-based photocatalysts. The nitrogen- and sulfur-doped in TiO2 which was prepared using sol–gel method. The prepared catalyst was characterized using XRD, SEM-EDX, FTIR, XPS, DRS, and BET analysis. The characterization revealed that Ti–N showed lower particle size, higher specific surface area, and low band-gap energy as compared to Ti–S. The photocatalytic degradation of 3,4-DCA using Ti–N showed better activity as compared to Ti–S and undoped TiO2. The findings revealed that various parameters, such as the initial pH of the solution to be degraded, catalyst loading, concentration of solution, and light intensity, exert their individual influence on the photocatalytic degradation of 3,4-DCA. The kinetics of degradation of 3,4-DCA followed two-regime LH model and rate constants were determined. The reaction constant and Langmuir adsorpt...

Fatty Methyl esters from vegetable oils for use as a diesel fuel

The world is confronted with the twin crisis of fossil fuel depletion and environmental degradation. The indiscriminate extraction and consumption of Fossil fuels have led to a reduction in petroleum. Due to the concern on the availability of recoverable fossil fuel reserves and environmental problems caused by the use of those fossil fuels, considerable attention has been given to biodiesel production. The methyl esters of vegetable oils, known as biodiesel becoming increasing popular, because of its potential as a green alternative fuel for diesel fuel. It has many advantages over conventional diesel fuels. These include biodegradable, non toxic, nil sulfur content, reduced aromatics. It can either be directly used in engine or can be blended with conventional diesel, and requires no engine modification. There are various methods available for the production of biodiesel such as micro emulsification, dilution, pyrolysis, transesterification and esterification, among which transesterification is the best process. Biodiesel is produced by transesterifying the parent oil or fat with an alcohol, usually methanol, in presence of a catalyst usually strong base such as NaOH or KOH or, preferably an increasingly more commonly alkoxide. The transesterification reaction variable that affect yield and purity of the product include molar ratio of alcohol to vegetable oil, type of catalyst, molar ratio of catalyst to oil, temperature and degree of refinement of vegetable oil. In this paper various vegetable oils transesterification was studied with the purpose of achieving the best conditions for biodiesel production.

Pyrolysis of polystyrene waste in the presence of activated carbon in conventional and microwave heating using modified thermocouple

Pyrolysis process was experimented using two types of heating source, namely conventional and microwave. Polystyrene (PS) plastic waste was used as feedstock in a batch reactor for both the conventional (slow pyrolysis) and microwave pyrolysis. The effect of activated carbon to polystyrene ratio on (i) yield of oil, gas and residues (ii) reaction temperature (iii) reaction time were studied. Quality of oil from pyrolysis of polystyrene were assessed for the possible applicability in fuel production. Microwave power of 450 W and polymer to activated carbon ratio of 10:1, resulted in the highest oil yield of 93.04 wt.% with a higher heating value of 45 MJ kg-1 and a kinematic viscosity of 2.7 cSt. Microwave heating when compared to conventional heating method, exhibits a reaction temperature and time of 330 °C in 5.5 min, whereas in conventional heating system it was 418 °C in 60 min. The gas chromatography-mass spectrometry analysis of liquid oil from microwave pyrolysis predominantly yields alkenes of 8.44 wt.%, α-methyl styrene 0.96 wt.%, condensed ring aromatics 23.21 wt.% and benzene derivatives 26.77 wt.% when the polystyrene to activated carbon ratio was 10:1. Significant factor of using microwave heating is the amount of energy converted (kWh) is lesser than conventional heating.