scholarly journals The role of Arthrobacter viscosus in the removal of Pb(II) from aqueous solutions

2017 ◽  
Vol 76 (7) ◽  
pp. 1726-1738 ◽  
Author(s):  
Raluca Maria Hlihor ◽  
Mihaela Roşca ◽  
Teresa Tavares ◽  
Maria Gavrilescu

The aim of this paper was to establish the optimum parameters for the biosorption of Pb(II) by dead and living Arthrobacter viscosus biomass from aqueous solution. It was found that at an initial pH of 4 and 26 °C, the dead biomass was able to remove 97% of 100 mg/L Pb(II), while the living biomass removed 96% of 100 mg/L Pb(II) at an initial pH of 6 and 28 ± 2 °C. The results were modeled using various kinetic and isotherm models so as to find out the mechanism of Pb(II) removal by A. viscosus. The modeling results indicated that Pb(II) biosorption by A. viscosus was based on a chemical reaction and that sorption occurred at the functional groups on the surface of the biomass. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy coupled with energy dispersive X-ray microanalysis (SEM-EDX) analyses confirmed these findings. The suitability of living biomass as biosorbent in the form of a biofilm immobilized on star-shaped polyethylene supports was also demonstrated. The results suggest that the use of dead and living A. viscosus for the removal of Pb(II) from aqueous solutions is an effective alternative, considering that up to now it has only been used in the form of biofilms supported on different zeolites.

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
H. Nourmoradi ◽  
Mehdi Khiadani ◽  
M. Nikaeen

Multicomponent adsorption of benzene, toluene, ethylbenzene, and xylene (BTEX) was assessed in aqueous solutions by montmorillonite modified with tetradecyl trimethyl ammonium bromide (TTAB-Mt). Batch experiments were conducted to determine the influences of parameters including loading rates of surfactant, contact time, pH, adsorbate concentration, and temperature on the adsorption efficiency. Scanning electron microscope (SEM) and X-ray diffractometer (XRD) were used to determine the adsorbent properties. Results showed that the modification of the adsorbent via the surfactant causes structural changes of the adsorbent. It was found that the optimum adsorption condition achieves with the surfactant loading rate of 200% of the cation exchange capacity (CEC) of the adsorbent for a period of 24 h. The sorption of BTEX by TTAB-Mt was in the order ofB<T<E<X. The experimental data were fitted by many kinetic and isotherm models. The results also showed that the pseudo-second-order kinetic model and Freundlich isotherm model could, respectively, be fitted to the experimental data better than other available kinetic and isotherm models. The thermodynamic study indicated that the sorption of BTEX with TTAB-Mt was achieved spontaneously and the adsorption process was endothermic as well as physical in nature. The regeneration results of the adsorbent also showed that the adsorption capacity of adsorbent after one use was 51% to 70% of original TTAB-Mt.


2016 ◽  
Vol 73 (11) ◽  
pp. 2747-2753 ◽  
Author(s):  
Wusong Kong ◽  
Hongxia Qu ◽  
Peng Chen ◽  
Weihua Ma ◽  
Huifang Xie

In this study, Cu2O-CuO/ZSM-5 nanocomposite was synthesized by the impregnation method, and its catalytic performance for the destruction of AO7 in aqueous solutions was investigated. The morphology, structure and surface element valence state of Cu2O-CuO/ZSM-5 were characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The operating conditions on the degradation of AO7 by Cu2O-CuO/ZSM-5, such as initial pH values, concentration of AO7 and catalyst dosage were investigated and optimized. The results showed that the sample had good catalytic activity for destruction of AO7 in the absence of a sacrificial agent (e.g. H2O2): it could degrade 91% AO7 in 140 min at 25 °C and was not restricted by the initial pH of the AO7 aqueous solutions. Cu2O-CuO/ZSM-5 exhibited stable catalytic activity with little loss after three successive runs. The total organic carbon and chemical oxygen demand removal efficiencies increased rapidly to 69.36% and 67.3% after 120 min of treatment by Cu2O-CuO/ZSM-5, respectively.


Column adsorption of the As (III) & As (V) using rice husk mediated carbon embedded silica (CES) and zeolite (Z-RHA) has been proved promising technique rather than the other conventional methods. The present work investigates the adsorption capability of newly manufactured CES and Z-RHA to remove As (III) & As (V) from aqueous solutions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive X-ray (EDX), and Transmission electron microscopy (TEM) analysis have been investigated for the characterization of synthesized materials. The effects of different parameters like initial concentrations, column diameter, column height, particle size distribution have been investigated. The maximum removal efficiency of CES adsorbents for As (III) is 98% and for As (V) is 85%, and of Z-RHA for As (III) is 95% and for As (V) is 92%. To describe the adsorption behavior the Langmuir and Freundlich isotherm models as well as to kinetics models like Adam-Bohart, Thomas, and Yoon Nelson model were applied. Finally, to dispose of the rice husk mediated adsorbents after arsenic treatment solidification has been done.


Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 131 ◽  
Author(s):  
Lie Yang ◽  
Hong Li ◽  
Jianming Xue ◽  
Liuyang He ◽  
Yongfei Ma ◽  
...  

The efficiencies of the nanoscale zero-valent iron (nZVI) and hydrothermal and nZVI-heat activation of peroxydisulfate (PS) were studied for the decomposition of chloramphenicol (CAP) in aqueous solutions. The nZVI heat combined with activation of PS provided a significant synergistic effect. A central composite design (CCD) with response surface methodology (RSM) was employed to explore the influences of single parameter and interactions of selected variables (initial pH, PS concentration, nZVI and temperature) on degradation rates with the purpose of condition optimization. A quadratic model was established based on the experimental results with excellent correlation coefficients of 0.9908 and 0.9823 for R2 and R2adj. The optimized experimental condition for 97.12% CAP removal was predicted with the quadratic model as 15 mg/L, 0.5 mmol/L, 7.08 and 70 °C for nZVI dosage, PS, initial pH, and temperature, respectively. This study demonstrated the effectiveness of RSM for the modeling and prediction of CAP removal processes. In the optimal condition, Fe2O3 and Fe3O4 were the predominant solid products after reactions based on X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis, which could also act as the activators along with the reaction. Overall, it could be concluded that hydrothermal enhanced nZVI activation of PS was a promising and efficient choice for CAP degradation.


2020 ◽  
Author(s):  
Neza Rahayu Palapa ◽  
Tarmizi Taher ◽  
Risfidian Mohadi ◽  
Addy Rachmat ◽  
Aldes Lesbani

Abstract In this work, CuAl/Biochar (BC) composite was prepared by the coprecipitation method. The materials were applied to remove malachite green in aqueous solution. These materials were characterized using XRD, FTIR, BET and SEM-EDX analyses. The composite material was confirmed by X-ray diffractograms with reflection (002) at 24o and the appearance of new peaks at 1095 cm -1 . The BET result of CuAl/BC composite has larger surface area is 168 m 2 /g than 46 m 2 /g for LDH. The morphologies of composite materials show agglomeration and micro particle size. The result of the adsorption study indicated the composite material follows pseudo-second-order (PSO) and Langmuir isotherm models. The maximum adsorption capacity of malachite green using CuAl/BC uptake is 164.316 mg/g. The thermodynamic analysis indicates that the malachite green adsorption is spontaneous, endothermic. Regeneration study of adsorbent CuAl/BC composite shows after four times reused, it still has high removal efficiency at 89%.


2016 ◽  
Vol 73 (10) ◽  
pp. 2422-2429 ◽  
Author(s):  
Jie Shi ◽  
Zhiwei Zhao ◽  
Zhijie Liang ◽  
Tianyi Sun

In this study, the potential of the oriental arborvitae leaves for the adsorption of Pb(II) from aqueous solutions was evaluated. Brunauer–Emmett–Teller analysis showed that the surface area of arborvitae leaves was 29.52 m2/g with pore diameter ranging from 2 to 50 nm. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy showed C—;C or C—;H, C—;O, and O—;C=O were the main groups on the arborvitae leaves, which were the main sites for surface complexation. Finally, effects of adsorbent dose, initial pH, contact time, and coexisting natural organic matters (humic acid (HA)) on the adsorption of Pb(II) were investigated. The results indicated that the pHZPC (adsorbents with zero point charge at this pH) was 5.3 and the adsorption reached equilibrium in 120 min. Isotherm simulations revealed that the natural arborvitae leaves exhibit effective adsorption for Pb(II) in aqueous solution, giving adsorptive affinity and capacity in an order of ‘no HA’ &gt; 5 mg/L HA &gt; 10 mg/L HA, and according to the Langmuir models, the maximum adsorptions of Pb(II) were 43.67 mg/g, 38.61 mg/g and 35.97 mg/g, respectively. The results demonstrated that the oriental arborvitae leaves showed high potentials for the adsorption of Pb(II) from aqueous solutions.


Author(s):  
Teba H. Mhawesh ◽  
Ziad T. Abd Ali

The potential application of granules of Granular brick waste as a low-cost sorbent for removal of Pb+2 ions from aqueous solutions has been studied. The properties of Granular brick waste were determined through several tests such as X-Ray diffraction , Energy dispersive X-ray, Scanning electron microscopy , and surface area. In batch tests, the influence of several operating parameters including contact time, initial concentration, agitation speed, and the dose of GBW was investigated. The best values of these parameters that provided maximum removal efficiency of lead (89.5 %) were 2.5 hr, 50 mg/L, 250 rpm, and 1.8 g/100mL, respectively. The sorption data obtained by batch experiments subjected to the three isotherm models called Langmuir, Freundlich and   Elovich. The results showed that the Langmuir isotherm model described well the sorption data (R2= 0.9866) in comparison with other models. The kinetic data were analyzed using two kinetic models called pseudo_first_order and pseudo_second_order. The pseudo-second-order kinetic model was found to agree well with the experimental data.


2013 ◽  
Vol 712-715 ◽  
pp. 482-486
Author(s):  
He Bin Shi ◽  
Yu Liu ◽  
Hong Zhong ◽  
Xing Tian ◽  
Ming Hang Liao

A middle grade siliceous phosphorite from Yunnan province was selected to treat Cd2+ bearing aqueous solutions. The siliceous phosphorite was tested by X-ray fluorescence spectrometer, X-ray diffraction, infrared spectrometer and scanning electron microscopy. The results present that the valuable mineral is nanostructured carbonated fluorapatite and the major gangue mineral is quartz. The amount of Cd2+ sorbed by the siliceous phosphorite tends to increase with the increase of initial pH or the initial Cd2+ concentration of the simulated waste water. The reaction process of Cd2+ removal from aqueous solutions is highly fitted with the pseudo-second order kinetic model. The results indicate that nanostructured carbonated fluorapatite bearing siliceous phosphorite can effectively immobilize aqueous Cd2+.


Author(s):  
Seyedeh Mahsa Seyed Danesh ◽  
Shahab Shariati ◽  
Hossein Faghihian

Objective: In this study, amine functionalized magnetite Kit-6 silica nanocomposite (Fe3O4@SiO2@Kit-6-NH2) was synthesized as an adsorbent for removing Carmoisine food dye from aqueous solutions. Method: The nanocomposite was chemically synthesized and was characterized by X-ray diffraction analysis (XRD), vi-brating sample magnetometer (VSM), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and Fourier transform infrared spectrometry (FT-IR). Taguchi orthogonal array experimental design method was used to op-timize the experimental conditions including adsorbent amount, pH of solution, amount of salt, the volume of sample and contact time. Pseudo first-order, pseudo second-order, intra-particle diffusion and Elovich kinetic models were investigated to study the kinetic parameters of sorption process. Results: The kinetic data corresponded to the pseudo second-order kinetic model with R2 = 0.9999. Also, adsorption data were analyzed using Langmuir, Freundlich and Temkin isotherm models. The results indicated that the data were well fitted to the Freundlich isotherm model (R2 = 0.9984, n=1.0786). The reusability tests showed the proposed nanocomposite can be used more than 8 cycles with removal efficiency higher than 90%. Conclusion: The applicability study of proposed nanocomposite proved its ability for efficient removal of Carmoisine dye from real aqueous samples.


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