Synthesis and Characterization of Non-Stoichiometric Li1.1Co0.3Fe2.1O4 Ferrite Nanoparticles For Humidity Applications

Abstract Humidity sensor plays a crucial role in determining the efficiency of materials and the precision of apparatuses. To measure and control humidity, a non-stoichiometric Li1.1Co0.3Fe2.1O4 mesopores sensor is synthesized by a modified citrate auto combustion technique. The XRD study confirms that prepared nanoparticles are cubic spinel structures having Fd3m space group. The crystallite size is approximate 36 nm. Thermal analyses measurements confirm that the samples become thermally stable starting from 600 °C. Additionally, the kinetic studies of the prepared samples are calculated via a pseudo-first-order kinetic model. The temperature dependence of AC conductivity is found to increase with increasing the temperature. These observations are explained in various models. The resistivity mechanism of humidity sensors is studied via Complex impedance spectroscopy (CIS). Its impedance data is fitting to a corresponding circuit, to achieve a simulation of the sample under study. This fitting is detected by the Nyquist plot (Cole-Cole). The obtained data confirms that the studied samples are very sensitive to humidity and can be commercially used as a humidity sensing element.

Download Full-text

Sawdust for the Removal of Heavy Metals from Water: A Review

Molecules ◽

10.3390/molecules26144318 ◽

2021 ◽

Vol 26 (14) ◽

pp. 4318

Author(s):

Elie Meez ◽

Abbas Rahdar ◽

George Z. Kyzas

Keyword(s):

Heavy Metals ◽

Adsorption Mechanism ◽

Freundlich Isotherm ◽

Order Kinetic ◽

Suitable Material ◽

Removal Of Heavy Metals ◽

Order Kinetic Model ◽

Pseudo Second Order ◽

And Control ◽

Environmental Agencies

The threat of the accumulation of heavy metals in wastewater is increasing, due to their abilities to inflict damage to human health, especially in the past decade. The world’s environmental agencies are trying to issue several regulations that allow the management and control of random disposals of heavy metals. Scientific studies have heavily focused on finding suitable materials and techniques for the purification of wastewaters, but most solutions have been rejected due to cost-related issues. Several potential materials for this objective have been found and have been compared to determine the most suitable material for the purification process. Sawdust, among all the materials investigated, shows high potential and very promising results. Sawdust has been shown to have a good structure suitable for water purification processes. Parameters affecting the adsorption mechanism of heavy metals into sawdust have been studied and it has been shown that pH, contact time and several other parameters could play a major role in improving the adsorption process. The adsorption was found to follow the Langmuir or Freundlich isotherm and a pseudo second-order kinetic model, meaning that the type of adsorption was a chemisorption. Sawdust has major advantages to be considered and is one of the most promising materials to solve the wastewater problem.

Download Full-text

Studies of Chromium Removal from Tannery Effluents by Dead Streptomyces Rimosus

Chemical Product and Process Modeling ◽

10.2202/1934-2659.1209 ◽

2008 ◽

Vol 3 (1) ◽

Cited By ~ 2

Author(s):

Mohamed Nasser Sahmoune ◽

Krim Louhab ◽

Aissa Boukhiar

Keyword(s):

Fractional Power ◽

Kinetic Studies ◽

Second Order ◽

Order Kinetic ◽

Streptomyces Rimosus ◽

Tannery Effluents ◽

Equilibrium Data ◽

Order Kinetic Model ◽

Pseudo Second Order ◽

Ph Range

Dead streptomyces rimosus was found to be an effective biosorbent for the removal of chromium from industrial tanning effluents. A sorption level of 65 mg/g was observed at pH 4.8 while the precipitation effect augmented this value at a higher pH range. Chromium desorption increased with decreasing desorption agents pH (including HCl and H2SO4) to a maximum value of 95% at approximately zero pH. The biosorption data of trivalent chromium by streptomyces rimosus has been used for kinetic studies based on fractional power, Elovich, pseudo-first order and pseudo-second order rate expressions. The time-dependent Cr (III) biosorption data were well-described by a pseudo-second-order kinetic model. The intraparticle diffusion is not the rate-limiting step for the whole reaction. It was found that the biosorption equilibrium data fit well with the Langmuir model.

Download Full-text

Equilibrium and Kinetic Studies for the Biosorption of Aqueous Nickel(II) Ions onto the Pseudomonas alcaligenes Biomass

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.171-172.41 ◽

2010 ◽

Vol 171-172 ◽

pp. 41-44

Author(s):

Xiao Cun Xiao ◽

Gai Xia Fang ◽

Er Li Zhao ◽

Lv Bin Zhai ◽

Jun Shuai Shi

Keyword(s):

Industrial Wastewater ◽

Chemical Interaction ◽

Kinetic Studies ◽

Synthetic Wastewater ◽

Order Kinetic ◽

Adsorption Capacities ◽

Order Kinetic Model ◽

Pseudo Second Order ◽

Pseudomonas Alcaligenes ◽

Batch Biosorption

The objective of this study is to assess the environmentaly friendly Ni(II) adsorption from synthetic wastewater using Pseudomonas alcaligenes biomass (PA-2). The ability of PA-2 to remove the Ni(II) ions was investigated by using batch biosorption procedure. The effects such as pH, dosage of biosorbent, Ni(II) initial concentration and sorbate–sorbent contact time and agitating speed on the adsorption capacities of PA-2 were studied. Biosorption equilibriums were rapidly established in about 60 min and the adsorption kinetics followed the pseudo-second order kinetic model. The maximum Ni(II) adsorption capacity determined from Langmuir isotherm were 82.23 mg/g PA-2 at pH 5.0, at 25±2°C and shaker speed 150 rpm, respectively. The carboxyl , hydroxyl and amino groups of the PA-2 were involved in chemical interaction with the Ni(II) ions depicted by Fourier transform infrared spectroscopic (FTIR) results. The study points to the potential of new use of Pseudomonas alcaligenes biomass as an effective biosorbent for the removal of Ni(II) and from environmental and industrial wastewater.

Download Full-text

Enhanced Biosorption of Pb(II) Ions from Aqueous Solutions onto Citric Acid Treated Aspergillus niger Biomass: Equilibrium and Kinetic Studies

Asian Journal of Chemistry ◽

10.14233/ajchem.2020.22346 ◽

2020 ◽

Vol 32 (3) ◽

pp. 508-514

Author(s):

Vinay Kumar Chintalapudi ◽

Ramya Krishna S.L. Kanamarlapudi ◽

Useni Reddy Mallu ◽

Sudhamani Muddada

Keyword(s):

Citric Acid ◽

Aspergillus Niger ◽

Kinetic Studies ◽

Order Kinetic ◽

Ftir Analysis ◽

Structural Variations ◽

Order Kinetic Model ◽

Pseudo Second Order ◽

Optimized Conditions ◽

Biosorption Kinetics

In the present study, initially Aspergillus niger was tested for biosorption of Pb(II) ions and then studied the effect of pretreatment for enhanced biosorption. It was found that the maximum biosorption potential was achieved with citric acid treatment (70.56 %) in comparison with the biomass without treatment (65.46 %) at a biosorbent dose of 20 mg/L, pH 4, 100 rpm, 37 ºC for 8 h. The optimized conditions for treated Aspergillus niger were determined by optimizing the biosorption parameters such as pH, temperature, biomass dose, incubation time and agitation speed. This study indicates that the citric acid treated Aspergillus niger is an effective biosorbent for removal of lead (II) at optimized conditions with the maximum biosorption potential of 83.6 % as compared to previous reported work. SEM-EDX and FTIR analysis showed the structural variations and the functional groups involved in lead biosorption, respectively. Biosorption kinetics showed that pseudo second order kinetic model as the better fit.

Download Full-text

Adsorption of Hexavalent Chromium from Aqueous Solution Using Chemically Activated Carbon Prepared from Locally Available Waste of Bamboo (Oxytenanthera abyssinica)

ISRN Environmental Chemistry ◽

10.1155/2014/438245 ◽

2014 ◽

Vol 2014 ◽

pp. 1-9 ◽

Cited By ~ 27

Author(s):

Tamirat Dula ◽

Khalid Siraj ◽

Shimeles Addisu Kitte

Keyword(s):

Activated Carbon ◽

Hexavalent Chromium ◽

Freundlich Isotherm ◽

Kinetic Studies ◽

Batch Adsorption ◽

Koh Activation ◽

Order Kinetic ◽

Oxytenanthera Abyssinica ◽

Equilibrium Data ◽

Order Kinetic Model

This study reports on the adsorption of Hexavalent Chromium from aqueous solutions using activated carbon prepared from bamboo (Oxytenanthera abyssinica) waste by KOH activation heating in an electrical furnace at 1073 K for 3 hrs. Batch adsorption experiments were also carried out as a function of pH, contact time, initial concentration of the adsorbate, adsorbent dosage, and temperature of the solution. Kinetic studies of the data showed that the adsorption follows the pseudo-second-order kinetic model. Thermodynamic parameters showed that adsorption on the surface of BWAC was feasible, spontaneous in nature, and exothermic between temperatures of 298 and 318 K. The equilibrium data better fitted the Freundlich isotherm model for studying the adsorption behavior of Hexavalent Chromium by BWAC. IR spectrum for loaded and unloaded BWAC was obtained using FT-IR spectrophotometer. Adsorption efficiency and capacity of Hexavalent Chromium were found to be 98.28% at pH 2 and 59.23 mg/g at 300 K.

Download Full-text

Kinetic Studies on Sorption of Textile Dyes Using Lamina and Petiole Parts of Eichhornia crassipes

Chemical Product and Process Modeling ◽

10.2202/1934-2659.1141 ◽

2008 ◽

Vol 3 (2) ◽

Author(s):

S Renganathan ◽

R Venkatakrishnan ◽

P Gautam ◽

Lima Rose Miranda ◽

M Velan

Keyword(s):

Diffusion Coefficient ◽

Kinetic Model ◽

Eichhornia Crassipes ◽

Kinetic Studies ◽

Reactive Dye ◽

The Other ◽

Order Kinetic ◽

Uptake Capacity ◽

Fast Red ◽

Order Kinetic Model

Sorption capacity of two different parts of Eichhornia crassipes such as Lamina and Petiole on a Basic dye (Basic Aurophine-O), Acidic dye (Acid Fast Red-A) and Reactive dye (Brill Red-5B) was studied in a batch system. The maximum equilibrium uptake capacity of petiole was 25.5 mg/g for Basic Aurophine-O, 23.1 mg/g for Acid Fast Red-A and 0.18 mg/g for Brill Red-5B. The equilibrium uptake capacity of petiole was found to be more in Basic Aurophine-O dye when compared to all other dyes studied. The maximum equilibrium uptake capacity of lamina was 27.0 mg/g for Basic Aurophine-O, 25.2 mg/g for Acid Fast Red-A and 4.2 mg/g for Brill Red-5B. The equilibrium uptake capacity of lamina was found to be more in Basic Aurophine-O when compared to Brill Red-5B and Acid Fast Red-A dyes studied in the present investigation. From the result, it was observed that the uptake capacity of dyes using E. crassipes part Lamina was found to be more when compared to the other E. crassipes part of Petiole used in the present study. Sorption results were found to be fitted very well with the Pseudo-second order kinetic model when compared to Pseudo-first order kinetic model. The intra particle diffusion coefficient (Ki) and diffusion coefficient (Di) obtained for the removal of dyes studied using Lamina was found to be more when compared to the other part of Petiole. The polynomial equations are developed and can be used as a ready reckoner equation to find out the percentage color removal of dyes studied in the present investigation at different period of time intervals.

Download Full-text

Acetylation of Pomelo Peel for the Production of Oil Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.955-959.2534 ◽

2014 ◽

Vol 955-959 ◽

pp. 2534-2538

Author(s):

Jun Chen Zou ◽

Xiao Yan Liu ◽

Wen Bo Chai ◽

Xin Ying Zhang ◽

Yu Sen Liu

Keyword(s):

Acetic Anhydride ◽

Correlation Coefficients ◽

Kinetic Studies ◽

Sorption Kinetics ◽

Lubricating Oil ◽

Order Kinetic ◽

Pomelo Peel ◽

Order Kinetic Model ◽

Pseudo Second Order ◽

Spilled Oil

Pomelo peel was esterified with acetic anhydride using 4-dimethyl-amino pyridine as a catalyst under reaction temperature of 60 °C and duration of 3 h. At 0.1 g 4-dimethyl-amino pyridine of the catalyst in 80 ml acetic anhydride, the highest sorption values of 14.95 g/g diesel and 18.39 g/g lubricating oil were achieved, which was found to be much higher than raw pomelo peel. FTIR and SEM studies produced evidence for acetylation. The sorption kinetics and reusability were studied. The kinetic studies show good correlation coefficients for a pseudo-second-order kinetic model. This work demonstrated that pomelo peel modified by acetic anhydride is an efficient and environment-friendly biosorbent for the removal of spilled oil.

Download Full-text

Equilibrium and Kinetic Studies of Benzene and Toluene Adsorption onto Microwave Irradiated-Coconut Shell Activated Carbon

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1043.219 ◽

2014 ◽

Vol 1043 ◽

pp. 219-223 ◽

Cited By ~ 1

Author(s):

Noor Shawal Nasri ◽

Jibril Mohammed ◽

Muhammad Abbas Ahmad Zaini ◽

Usman Dadum Hamza ◽

Husna Mohd. Zain ◽

...

Keyword(s):

Activated Carbon ◽

Kinetic Studies ◽

Coconut Shell ◽

Maximum Adsorption Capacity ◽

Order Kinetic ◽

Volatile Organic ◽

Equilibrium Data ◽

Order Kinetic Model ◽

Pseudo Second Order ◽

Coconut Shell Activated Carbon

Concern about environmental protection has increased over the years and the presence of volatile organic compounds (VOCs) in water poses a threat to the environment. In this study, coconut shell activated carbon (PHAC) was produced by potassium hydroxide activation via microwave for benzene and toluene removal. Equilibrium data were fitted to Langmuir, Freundlich and Tempkin isotherms with all the models having R2 > 0.94. The equilibrium data were best fitted by Langmuir isotherm, with maximum adsorption capacity of 212 and 238mg/g for benzene and toluene, respectively. The equilibrium parameter (RL) falls between 0 and 1 confirming the favourability of the Langmuir model. Pseudo-second-order kinetic model best fitted the kinetic data. The PHAC produced can be used to remediate water polluted by VOCs.

Download Full-text

Lead removal using Fallen Coffee Plant Leaves (FCPL) powder: Characterization, Equilibrium, Kinetics and Thermodynamic studies

E3S Web of Conferences ◽

10.1051/e3sconf/202130901077 ◽

2021 ◽

Vol 309 ◽

pp. 01077

Author(s):

M Tukaram Bai ◽

Ch. I. A. Raju ◽

V Sridevi ◽

Nalluri Chittibabu ◽

P Venkateswarlu

Keyword(s):

Correlation Coefficient ◽

Kinetic Studies ◽

Lead Removal ◽

Order Kinetic ◽

Plant Leaves ◽

Coffee Plant ◽

Freundlich Isotherms ◽

Equilibrium Data ◽

Order Kinetic Model ◽

Pseudo Second Order

Biosorption of lead onto Fallen Coffee Plant leaves (FCPL) powder from an aqueous solution was studied in the present study. The characterization of FCPL powder was done by FTIR, XRD, SEM and BET. The equilibrium agitation time for lead biosorption is 60 min. The optimum pH and dosage values are 5.2 and 20 g/L respectively. In the range of variables studied, percentage biosorption is increased from 75.1 to 95.5 %. The maximum uptake capacity of 3.664 mg/g is obtained at 303 K. In the present investigation the equilibrium data was well explained by Langmuir, Redlich-Peterson with a correlation coefficient of 0.99, and followed by Temkin and Freundlich isotherms. The kinetic studies reveal that the biosorption system obeyed the pseudo second order kinetic model by considering the correlation coefficient value as 0.99. From the values of ∆S, ∆H and ∆G it is observed that the biosorption of lead onto Fallen coffee plant leaves(FCPL) powder was irreversible, endothermic and spontaneous.

Download Full-text

Investigating the synergistic effect of UV/PS/TiO2 and UV/PI/TiO2 processes on paraquat herbicide degradation in media aqueous: statistical optimization, kinetic study, and estimation of electrical energy consumption

10.21203/rs.3.rs-277799/v1 ◽

2021 ◽

Author(s):

Azam Ghavi ◽

Ghadamali Bagherian ◽

Hadi Rezaei Vahidian

Keyword(s):

Energy Consumption ◽

Optimum Condition ◽

Kinetic Studies ◽

Electrical Energy ◽

Degradation Efficiency ◽

Order Kinetic ◽

Electrical Energy Consumption ◽

Herbicide Degradation ◽

Oxidant Concentration ◽

Order Kinetic Model

Abstract In this paper, the performance of UV/PS/TiO2 and UV/PI/TiO2 as hybrid AOPs for degradation of paraquat (PQ) herbicide in aqueous solution has been studied. The effect of several factors such as UV irradiation, initial oxidant concentration, nano-TiO2 (TiO2NPs) dosage, and pH on the degradation efficiency was investigated. Process optimization was performed by Central Composite Design (CCD) and response surface methodology (RSM) for 30 mgL− 1 of herbicide at 25 ˚C and 40 min. Based on the results, for UV/PS/TiO2 process a degradation efficiency of 83% was obtained in the optimum condition of initial PS concentration of 400 mgL− 1, initial TiO2NPs concentration of 150 mgL− 1, and pH = 6.3. Also for UV/PI/TiO2 process, 87% degradation efficiency was achieved in the optimum condition of initial PI concentration of 88 mgL− 1, initial TiO2NPs dosage of 125.5 mgL− 1, and pH of 7.5. Mineralization efficiency of the PQ solution by using PS and PI were about 47.5% and 57%, respectively after 80 min. Kinetic studies showed that both process follow pseudo-first-order kinetic model and their kinetic constants were 0.0299 min− 1 for PS process and 0.0604 min− 1 for PI process. Electrical energy consumption was estimated about 481.60 kWh/m3 for PS process and 238.41 kWh/m3 for PI process.

Download Full-text