scholarly journals Removal of 4-chlorophenol from aqueous solution by granular activated carbon/nanoscale zero valent iron based on Response Surface Modeling

2017 ◽  
Vol 43 (4) ◽  
pp. 13-25 ◽  
Author(s):  
Monireh Majlesi ◽  
Yalda Hashempour
Keyword(s):  
Activated Carbon ◽  
Phenolic Compounds ◽  
Response Surface ◽  
Zero Valent Iron ◽  
Quadratic Model ◽  
Low Concentrations ◽  
Operational Variables ◽  
Nanoscale Zero Valent Iron ◽  
Priority Order

AbstractThe phenolic compounds are known as priority pollutants, even in low concentrations, as a result of their toxicity and non-biodegradability. For this reason, strict standards have been established for them. In addition, chlorophenols are placed in the 38th to 43th in highest priority order of toxic pollutants. As a consequence, contaminated water or wastewaters with phenolic compounds have to be treated before discharging into the receiving water. In this study, Response Surface Methodology (RSM) has been used in order to optimize the effect of main operational variables responsible for the higher 4-chlorophenol removal by Activated Carbon-Supported Nanoscale Zero Valent Iron (AC/NZVI). A Box-Behnken factorial Design (BBD) with three levels was applied to optimize the initial concentration, time, pH, and adsorbent dose. The characterization of adsorbents was conducted by using SEM-EDS and XRD analyses. Furthermore, the adsorption isotherm and kinetics of 4-chlorophenol on AC and AC/NZVI under various conditions were studied. The model anticipated 100% removal efficiency for AC/NZVI at the optimum concentration (5.48 mg 4-chlorophenol/L), pH (5.44), contact time (44.7 min) and dose (0.65g/L). Analysis of the response surface quadratic model signified that the experiments are accurate and the model is highly significant. Moreover, the synthetic adsorbent is highly efficient in removing of 4-chlorophenol.

Performance of granular activated carbon/nanoscale zero valent iron for removal of humic substances from aqueous solution based on Experimental Design and Response Surface Modeling

2017 ◽  
Vol 20 (1) ◽  
pp. 57-68
Keyword(s):  
Activated Carbon ◽  
Response Surface ◽  
Humic Substances ◽  
Contact Time ◽  
Xrd Analysis ◽  
Zero Valent Iron ◽  
Optimum Conditions ◽  
Initial Concentration ◽  
Nanoscale Zero Valent Iron ◽  
Adsorbent Dose

Response surface methodology has been used to design experiments and to optimize the effect of independent variables responsible for higher adsorption of humic substances by activated carbon supported nanoscale zero-valent iron from aqueous solutions. The variables of initial concentration, time, pH, adsorbent dose was examined. The characterization of NZVI/AC was carried out by SEM-EDS and XRD analysis. The adsorption isotherms and kinetics of humic substances on AC and NZVI/AC were studied. The findings showed that the particle size of synthesis NZVI were in the range 20-50nm. The experimental data followed the Langmuir isotherm and pseudo-second kinetic model. For AC, optimum conditions of initial concentration, pH, contact time, and adsorbent dose were 5 mg L-1, 4.43, 46.28 min, and 1.5 g L-1, respectively. For NZVI/AC, optimum conditions of initial concentration, pH, contact time, and adsorbent dose were 5.48 mg L-1, 5.44, 44.7 min, 0.65 g L-1, respectively. Predicted removal efficiency by Box-Benken models for activated carbon and NZVI were 60 and 100 percent, respectively.

scholarly journals Fenton-Like Oxidation of Antibiotic Ornidazole Using Biochar-Supported Nanoscale Zero-Valent Iron as Heterogeneous Hydrogen Peroxide Activator

2020 ◽  
Vol 17 (4) ◽  
pp. 1324 ◽  
Author(s):  
Yanchang Zhang ◽  
Lin Zhao ◽  
Yongkui Yang ◽  
Peizhe Sun
Keyword(s):  
Oxidation Process ◽  
Zero Valent Iron ◽  
Order Kinetic ◽  
Mass Ratio ◽  
Promising Alternative ◽  
Nanoscale Zero Valent Iron ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
H2o2 System

Biochar (BC)-supported nanoscale zero-valent iron (nZVI-BC) was investigated as a heterogeneous Fenton-like activator to degrade the antibiotic ornidazole (ONZ). The characterization of nZVI-BC indicated that BC could enhance the adsorption of ONZ and reduce the aggregation of nZVI. Thus, nZVI-BC had a higher removal efficiency (80.1%) than nZVI and BC. The effects of parameters such as the nZVI/BC mass ratio, pH, H2O2 concentration, nZVI-BC dose, and temperature were systematically investigated, and the removal of ONZ followed a pseudo-second-order kinetic model. Finally, possible pathways of ONZ in the oxidation process were proposed. The removal mechanism included the adsorption of ONZ onto the surface of nZVI-BC, the generation of •OH by the reaction of nZVI with H2O2, and the oxidation of ONZ. Recycling experiments indicated that the nZVI-BC/H2O2 system is a promising alternative for the treatment of wastewater containing ONZ.

scholarly journals Nanoscale Zero-Valent Iron for Sulfide Removal from Digested Piggery Wastewater

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Sheng-Hsun Chaung ◽  
Pei-Fung Wu ◽  
Yu-Lin Kao ◽  
Weile Yan ◽  
Hsing-Lung Lien
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Surface Characterization ◽  
Iron Sulfide ◽  
Ph Effect ◽  
Zero Valent Iron ◽  
Laboratory Studies ◽  
Sulfide Removal ◽  
Nanoscale Zero Valent Iron ◽  
The Impact

The removal of dissolved sulfides in water and wastewater by nanoscale zero-valent iron (nZVI) was examined in the study. Both laboratory batch studies and a pilot test in a 50,000-pig farm were conducted. Laboratory studies indicated that the sulfide removal with nZVI was a function of pH where an increase in pH decreased removal rates. The pH effect on the sulfide removal with nZVI is attributed to the formation of FeS through the precipitation of Fe(II) and sulfide. The saturated adsorption capacities determined by the Langmuir model were 821.2, 486.3, and 359.7 mg/g at pH values 4, 7, and 12, respectively, for nZVI, largely higher than conventional adsorbents such as activated carbon and impregnated activated carbon. The surface characterization of sulfide-laden nZVI using XPS and TGA indicated the formation of iron sulfide, disulfide, and polysulfide that may account for the high adsorption capacity of nZVI towards sulfide. The pilot study showed the effectiveness of nZVI for sulfide removal; however, the adsorption capacity is almost 50 times less than that determined in the laboratory studies during the testing period of 30 d. The complexity of digested wastewater constituents may limit the effectiveness of nZVI. Microbial analysis suggested that the impact of nZVI on the change of microbial species distribution was relatively noticeable after the addition of nZVI.

Preparation of Activated Carbon Fiber Supported Nanoscale Fe0 for Simultaneous Adsorption and Dechlorination of Chloroform in Water

2011 ◽  
Vol 399-401 ◽  
pp. 1386-1391
Author(s):  
Yuan Yuan Wang ◽  
Qian Huang ◽  
Qi Ming Xian ◽  
Cheng Sun
Keyword(s):  
Activated Carbon ◽  
Carbon Fiber ◽  
Organic Contaminants ◽  
Ferrous Sulfate ◽  
Chemical Reduction ◽  
Activated Carbon Fiber ◽  
Zero Valent Iron ◽  
Simultaneous Adsorption ◽  
Nanoscale Zero Valent Iron ◽  
Chlorinated Organic

Nanoscale zero-valent iron (NZVI) particles were supported onto activated carbon fiber (ACF) by impregnating ACF with ferrous sulfate followed by chemical reduction with NaBH4. A new kind of material ACF/NZVI with approximate 9.64% (wt%) iron was prepared, the structure of the prepared ACF/NZVI was characterized bySEM, XRD and BET. The average NZVI particles with the size of 8.1nm were well dispersed on the ACF. The activity of the prepared ACF/NZVI was evaluated for removing chloroform in water. When 5g/L of ACF/NZVI was added into water with 10 mg/L chloroform, more than 90% of chloroform in water was removed in 48h at pH7.0 and (25±2) ºС. The dechlorination and adsorption of chloroform on ACF/NZVI took place at the same time. The total Chloroform removal by ACF/NZVI was 53.1% after 48h. Consequently, ACF/NZVI exhibits the potential of simultaneous adsorption and dechlorination for chlorinated organic contaminants in water.

scholarly journals Adsorption of phosphorus onto nanoscale zero-valent iron/activated carbon: removal mechanisms, thermodynamics, and interferences

2022 ◽  
Author(s):  
Adel Adly ◽  
Nagwan G. Mostafa ◽  
Abdelsalam Elawwad
Keyword(s):  
Activated Carbon ◽  
Removal Efficiency ◽  
Kinetic Models ◽  
Average Particle Size ◽  
Zero Valent Iron ◽  
Solution Temperature ◽  
Average Particle ◽  
Phosphorus Adsorption ◽  
Removal Mechanisms ◽  
Nanoscale Zero Valent Iron

Abstract This study investigated removal mechanisms, thermodynamics, and interferences of phosphorus adsorption onto nanoscale zero-valent iron (nZVI)/activated carbon composite. Activated carbon was successfully used as support for nZVI particles to overcome shortcomings of using nZVI include its tendency to aggregate and separation difficulties. A comprehensive characterization was done for the composite particles, which revealed a high specific surface area of 72.66 m2/g and an average particle size of 37 nm. Several adsorption isotherms and kinetic models have been applied to understand the removal mechanisms. Adsorption isotherm is best fitted by Freundlich and Langmuir models, which indicates that the estimated maximum phosphorus adsorption capacity is 53.76 mg/g at pH 4. Adsorption kinetics showed that the chemisorption process behaved according to a pseudo-second-order model. An adsorption mechanism study conducted using the intra-particle diffusion and Boyd kinetic models indicated that the adsorption rate is limited by surface diffusion. A thermodynamic study showed that phosphorus removal efficiency increased as the solution temperature increased from 15 to 37 °C. Finally, the results of an interference study showed that the presence of Ni2+, Cu2+, Ca2+, Na+ cations, nitrate ions (), and sodium acetate improves removal efficiency, while the presence of sulfate ions () and urea reduces removal efficiency.

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