scholarly journals Photocatalytic Degradation of Naphthalene By UV/Zno: Kinetics, Influencing Factors and Mechanisms

2021 ◽  
Vol 37 (1) ◽  
pp. 65-70
Author(s):  
Aram Dokht Khatibi ◽  
Kethineni Chandrika ◽  
Ferdos Kord Mostafapour ◽  
Ali Akbar Sajadi ◽  
Davoud Balarak

Conventional wastewater treatment is not able to effectively remove Aromatic hydrocarbons such as Naphthalene, so it is important to remove the remaining antibiotics from the environment. The aim of this study was to evaluate the efficiency of UV/ZnOphotocatalytic process in removing naphthalene antibiotics from aqueous solutions.This was an experimental-applied study that was performed in a batch system on a laboratory scale. The variables studied in this study include the initial pH of the solution, the dose of ZnO, reaction time and initial concentration of Naphthalene were examined. The amount of naphthalene in the samples was measured using GC.The results showed that by decreasing the pH and decreasing the initial concentration of naphthalene and increasing the contact time, the efficiency of the process was developed. However, an increase in the dose of nanoparticles to 0.8 g/L had enhance the efficiency of the process was enhanced, while increasing its amount to values higher than 0.8 g/L has been associated with a decrease in removal efficiency.The results of this study showed that the use of UV/ZnOphotocatalytic process can be addressed as a well-organized method to remove naphthalene from aqueous solutions.

2012 ◽  
Vol 14 (2) ◽  
pp. 22-28 ◽  
Author(s):  
Akbar Esmaeili ◽  
Mona Kalantari ◽  
Betsabe Saremnia

Biosorption of Pb (II) from aqueous solutions by modified of two kinds of marine algae, Sargassum glaucescens and Gracilaria corticata In this research, the batch removal of Pb2+ ions from wastewater and aqueous solution with the use o two different modified algae Gracilaria corticata (red algae) and Sargassum glaucescens (brown algae) was examined. The experiment was performed in a batch system and the effect of the pH solution; initial concentration and contact time on biosorption by both biomasses were investigated and compared. When we used S. glaucescens as a biosorbent, the optima conditions of pH, Pb2+ concentration and equilibrium time were at 5, 200 mg/L and 70 min, in the range of 95.6% removal. When G. corticata was used for this process, pH 3, 15 mg/L pb2+ concentration and 50 min contact time, resulted in the maximum removal (86.4%). The equilibrium adsorption data are fitted to the Frundlich and Langmuir isotherm model, by S. glaucescens and G. corticata, respectively. The pb2+ uptake by both biosorbent was best described by the second-order rate model.


Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1437
Author(s):  
Chih Ming Ma ◽  
Bo-Yuan Yang ◽  
Gui-Bing Hong

Hydrogel beads based on the husk of agarwood fruit (HAF)/sodium alginate (SA), and based on the HAF/chitosan (CS) were developed for the removal of the dyes, crystal violet (CV) and reactive blue 4 (RB4), in aqueous solutions, respectively. The effects of the initial pH (2–10) of the dye solution, the adsorbent dosage (0.5–3.5 g/L), and contact time (0–540 min) were investigated in a batch system. The dynamic adsorption behavior of CV and RB4 can be represented well by the pseudo-second-order model and pseudo-first-order model, respectively. In addition, the adsorption isotherm data can be explained by the Langmuir isotherm model. Both hydrogel beads have acceptable adsorption selectivity and reusability for the study of selective adsorption and regeneration. Based on the effectiveness, selectivity, and reusability of these hydrogel beads, they can be treated as potential adsorbents for the removal of dyes in aqueous solutions.


2012 ◽  
Vol 66 (8) ◽  
pp. 1699-1707 ◽  
Author(s):  
A. K. Giri ◽  
R. K. Patel ◽  
P. C. Mishra

In this work, the biosorption of As(V) from aqueous solutions by living cells of Bacillus cereus has been reported. The batch biosorption experiments were conducted with respect to biosorbent dosage 0.5 to 15 g/L, pH 2 to 9, contact time 5 to 90 min, initial concentration 1 to 10 mg/L and temperature 10 to 40 °C. The maximum biosorption capacity of B. cereus for As(V) was found to be 30.04 at pH 7.0, at optimum conditions of contact time of 30 min, biomass dosage of 6 g/L, and temperature of 30 ± 2 °C. Biosorption data were fitted to linearly transformed Langmuir isotherms with R2 (correlation coefficient) >0.99. Bacillus cereus cell surface was characterized using AFM and FTIR. The metal ions were desorbed from B. cereus using both 1 M HCl and 1 M HNO3. The pseudo-second-order model was successfully applied to predict the rate constant of biosorption.


NANO ◽  
2019 ◽  
Vol 14 (02) ◽  
pp. 1950027
Author(s):  
Ziyan Yang ◽  
Xiaoli Yang ◽  
Rui Hu ◽  
Junfeng Wu

Many current sorbents are limited for U(VI) concentration from aqueous solutions due to their inappropriate structures and surface chemistry. Herein, we report the rapid sorption of U(VI) with high capacities and selectivity by amidoxime modified ordered mesoporous SBA-15 with two typical morphologies (i.e., rods and plates) via a post-grafting method. Variables of the geochemical conditions (contact time, pH value, initial concentration, temperature and coexisting metal ions) are investigated. The results show that the mesostructures including morphologies and pore length of SBA-15 perform the dominant function for the fast sorption kinetics (10[Formula: see text]min for plates, 20[Formula: see text]min for rods), while the modified amidoxime groups make the excellent U(VI) sorption capacities (646.2[Formula: see text]mg[Formula: see text][Formula: see text][Formula: see text]g[Formula: see text] for plates, 499.8[Formula: see text]mg[Formula: see text][Formula: see text][Formula: see text]g[Formula: see text] for rods at pH 5.0 and [Formula: see text] 298.15[Formula: see text]K) and high selectivity possible. U(VI) adsorbed amidoxime-functionalized SBA can also be effectively regenerated by HCl solutions and reused well after six cycles.


2012 ◽  
Vol 724 ◽  
pp. 61-64
Author(s):  
Ying Li ◽  
Xiao Yan Lin ◽  
Zhe Chen ◽  
Xue Guang Luo ◽  
Wei Li Zuo

A composite membrane of thermoplastic carboxymethyl cellulose (TCMC) /PLA was prepared by electrospinning process, and crossliked by epichlorohydrin solution at different temperature. The cross-linking temperature was optimized by characterizing the morphology and tensile strength of the film. The optimal cross-linking temperature was 50°C. A composite membrane was used to remove Cu2+ from aqueous solutions, and the effects of initial concentration of Cu2+ and contact time on the removal efficiency of Cu2+ were investigated. The removal efficiency of Cu2+ was 13.78%, at the initial concentration of 40 mg·L-1 and contact time of 30s.


2016 ◽  
Vol 721 ◽  
pp. 143-148 ◽  
Author(s):  
Nora Noureddine ◽  
Samia Benhammadi ◽  
Fouad Kara ◽  
Hakim Aguedal ◽  
Abdelkader Iddou ◽  
...  

A bacterial strain Pseudomonas aeruginosa isolated from an uncontaminated soil has been used for the removal of hexavalent chromium (Cr (VI)). The experiments were carried out in batch system in a culture broth. The results obtained have shown that 100% of Cr (VI) are removed. Contact time, initial concentration of the hexavalent chromium, temperature, as well as the nature of the culture broth have influenced this elimination. To the initial concentration of 20g/L of Cr (VI) the elimination rates are lower, while the reverse occurs for an initial concentration of 8g/L. This study allows considering the use of Pseudomonas aeruginosa in the treatment of water polluted by toxic heavy metals such as Cr (VI).


2010 ◽  
Vol 8 (3) ◽  
pp. 696-701 ◽  
Author(s):  
Ayman Massoud ◽  
F. Abou El-Nour ◽  
H. Killa ◽  
U. Seddik

AbstractThis work assesses the potential of an adsorptive material, Dowex 50w-x8, for the separation of indium ions from cadmium ions in aqueous media. The adsorption behavior of Dowex 50 w-x8 for indium and cadmium ions was investigated. The effect of pH, initial concentration of metal ions, the weight of resins, and contact time on the sorption of each of the metal ions were determined. It was found that the adsorption percentage of the indium ions was more than 99% at pH 4.0. The result shows that In (III) was most strongly extracted, while Cd(II) was slightly extracted at this pH value. The recovery of In(III) and Cd(II) ions is around 98% using hydrochloric acid as the best eluent.


2011 ◽  
Vol 183-185 ◽  
pp. 1378-1382 ◽  
Author(s):  
Qing Dong Qin ◽  
Jun Ma ◽  
Da Fang Fu

All-silica zeolite beta (BEA) was tested for the ability to remove nitrobenzene and benzoic acid from aqueous solution. The effect of contact time, temperature, initial concentration and initial pH were investigated in a batch reactor system. Adsorption of nitrobenzene decreased with increase in temperature. The equilibrium isotherm was L-shaped. Nitrobenzene adsorption was independent of pH. Adsorption of benzoic acid increased with increasing temperature from 5 °C to 22 °C and decreased with increasing temperature from 22°C to 32 °C. The equilibrium isotherm was approximately S-shaped. Benzoic acid adsorption was dependent of pH. At pH8.0, benzoic acid can also be adsorbed effectively. The results above confirmed that BEA had the potential to be utilized as relatively effective adsorbent for nitrobenzene and benzoic acid removal.


2019 ◽  
Vol 6 (2) ◽  
pp. 66-74 ◽  
Author(s):  
Raziyeh Hosseini ◽  
Mohammad Hossein Sayadi ◽  
Hossein Shekari

The research was conducted with an aim to assess the efficiency of copper oxide nanoparticles as an adsorbent to remove Ni and Cr. The effect of pH, adsorbent dosage, contact time, initial concentration of metals (Ni and Cr) on the adsorption rate was evaluated and removal of these elements from aqueous solutions was measured using Atomic Absorption Spectrum System (Conter AA700). Moreover, the kinetic and isotherm besides thermodynamic adsorption models were assessed. The highest Ni and Cr removal rate occurred at an optimal pH of 7, and an initial concentration of 30 mg/L, a time period of 30 minutes, and 1 g/L of copper oxide nanoparticles. In fact, with the increase of adsorbent dosage and contact time, the removal efficiency increased and with initial concentration increase of Ni and Cr ions, the removal efficiency reduced. The correlation coefficient of isotherm models viz. Langmuir, Freundlich, Temkin, Redlich-Peterson, and Koble-Corrigan showed that Ni and Cr adsorption via copper oxide nanoparticles better follows the Langmuir model in relation to other models. The results showed that kinetic adsorption of Ni and Cr via copper oxide nanoparticles follows the second order pseudo model with correlation coefficients above 0.99. In addition, the achieved thermodynamic constants revealed that the adsorption process of metals (i.e., Ni and Cr) via copper oxide nanoparticles was endothermic and spontaneous and the reaction enthalpy values for these metals were 17.727 and 11.862 kJ/mol, respectively. In conclusion, copper oxide nanoparticles can be used as effective and environmentally compatible adsorbents to remove Ni and Cr ions from the aqueous solutions


2012 ◽  
Vol 518-523 ◽  
pp. 2708-2711 ◽  
Author(s):  
Ming Zhou ◽  
Hang Xu ◽  
Shu Fa Zhu ◽  
Ya Na Liu

The possible use of biowaste-banana skin as an alternative, low-cost biosorbent and reductant for removal of Cr from aqueous solutions was investigated. Effects of pH, contact time, Cr(VI) initial concentration and temperature on the reduction and biosorption of Cr by banana skin were studied. Experimental results showed that 1 g of dried banana skin could reduce about 230 mg of Cr(VI) to Cr(III), at the condition of 30°C, pH 2 and 300 rpm. The maximum Qeq of Cr(III) by banana skin was 6.3mg g-1 at the Cr(VI) initial concentration of 200mg L-1, 30°C , pH 2 and 300 rpm.


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