Correlations between pore textures of activated carbons and Langmuir constants – case studies on methylene blue and congo red adsorption

Toxin Reviews ◽  
2020 ◽  
pp. 1-11
Author(s):  
Fadina Amran ◽  
Muhammad Abbas Ahmad Zaini
Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1917
Author(s):  
Guangpu Zhang ◽  
Rong Wo ◽  
Zhe Sun ◽  
Gazi Hao ◽  
Guigao Liu ◽  
...  

A magnetic metal−organic frameworks adsorbent (Fe3O4@MIL-53(Al)) was prepared by a typical solvothermal method for the removal of bisphenol A (BPA), tetracycline (TC), congo red (CR), and methylene blue (MB). The prepared Fe3O4@MIL-53(Al) composite adsorbent was well characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and fourier transform infrared spectrometer (FTIR). The influence of adsorbent quantity, adsorption time, pH and ionic strength on the adsorption of the mentioned pollutants were also studied by a UV/Vis spectrophotometer. The adsorption capacities were found to be 160.9 mg/g for BPA, 47.8 mg/g for TC, 234.4 mg/g for CR, 70.8 mg/g for MB, respectively, which is superior to the other reported adsorbents. The adsorption of BPA, TC, and CR were well-fitted by the Langmuir adsorption isotherm model, while MB followed the Freundlich model, while the adsorption kinetics data of all pollutants followed the pseudo-second-order kinetic models. The thermodynamic values, including the enthalpy change (ΔH°), the Gibbs free energy change (ΔG°), and entropy change (ΔS°), showed that the adsorption processes were spontaneous and exothermic entropy-reduction process for BPA, but spontaneous and endothermic entropy-increasing processes for the others. The Fe3O4@MIL-53(Al) was also found to be easily separated after external magnetic field, can be a potential candidate for future water treatment.


Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 384
Author(s):  
Ahmed Labena ◽  
Ahmed E. Abdelhamid ◽  
Abeer S. Amin ◽  
Shimaa Husien ◽  
Liqaa Hamid ◽  
...  

Biosorption is a bioremediation approach for the removal of harmful dyes from industrial effluents using biological materials. This study investigated Methylene blue (M. blue) and Congo red (C. red) biosorption from model aqueous solutions by two marine macro-algae, Ulva fasciata and Sargassum dentifolium, incorporated within acrylic fiber waste to form composite membranes, Acrylic fiber-U. fasciata (AF-U) and Acrylic fiber-S. dentifolium (AF-S), respectively. The adsorption process was designed to more easily achieve the 3R process, i.e., removal, recovery, and reuse. The process of optimization was implemented through one factor at a time (OFAT) experiments, followed by a factorial design experiment to achieve the highest dye removal efficiency. Furthermore, isotherm and kinetics studies were undertaken to determine the reaction nature. FT-IR and SEM analyses were performed to investigate the properties of the membrane. The AF-U membrane showed a significant dye removal efficiency, of 88.9% for 100 ppm M. blue conc. and 79.6% for 50 ppm C. red conc. after 240 min sorption time. AF-S recorded a sorption capacity of 82.1% for 100 ppm M. blue conc. after 30 min sorption time and 85% for 100 ppm C. red conc. after 240 min contact time. The membranes were successfully applied in the 3Rs process, in which it was found that the membranes could be used for five cycles of the removal process with stable efficiency.


2017 ◽  
Vol 11 (5) ◽  
pp. 538-545 ◽  
Author(s):  
Mahmoud Nasrollahzadeh ◽  
S. Mohammad Sajadi ◽  
Mehdi Maham ◽  
Hamid Reza Dasmeh

2019 ◽  
Vol 7 (2) ◽  
pp. 240-246
Author(s):  
Kaur Harpreet ◽  
Kaur Harpreet ◽  
Vandana Kamboj ◽  
Vandana Kamboj

Water is the most crucial thing to mankind and so its contamination by various agencies is posing a threat to the natural balance. So, in the present work, the efficiency of various adsorbents derived from plant waste, to remove different dyes from aqueous solution was evaluated. Parameters for study were contact time, concentration and pH. Various combinations of plant ashes were used for the study. It was found that adsorbent prepared from the combination of orange peels, pomegranate and banana peels ashes, exhibited good adsorption capacity for methylene blue, congo red and crystal violet. All these dyes were completely removed from the aqueous solution while methyl orange was not removed. Congo red was removed completely within 40 min of contact with the adsorbent while methyl orange took 3 hrs to be removed to the extent of 48% only. The adsorption coefficient of congo red was found to be 2.33 while value for methylene blue and crystal violet was 1 and 1.66 respectively. The characterization of adsorbent was done by Scanning Electron Microscopy and IR spectroscopy. SEM image revealed the surface of adsorbent to be made of differential pores. From the results it became evident that the low-cost adsorbent could be used as a replacement for costly traditional methods of removing colorants from water.


2018 ◽  
Vol 83 (1) ◽  
pp. 107-120 ◽  
Author(s):  
Zdravka Velkova ◽  
Gergana Kirova ◽  
Margarita Stoytcheva ◽  
Velizar Gochev

Pretreated waste Streptomyces fradiae biomass was utilized as an eco-friendly sorbent for Congo Red (CR) and Methylene Blue (MB) removal from aqueous solutions. The biosorbent was characterized by Fourier transform infrared spectroscopy. Batch experiments were conducted to study the effect of pH, biosorbent dosage, initial concentration of adsorbates, contact time and temperature on the biosorption of the two dyes. The equilibrium adsorption data were analysed using Freundlich and Langmuir models. Both models fitted well the experimental data. The maximum biosorption capacity of the pretreated Streptomyces fradiae biomass was 46.64 mg g-1 for CR and 59.63 mg g-1 for MB, at a pH 6.0, with the contact time of 120 min, the biosorbent dosage of 2 g dm-3 and the temperature of 298 K. Lagergren and Ho kinetic models were used to analyse the kinetic data obtained from different batch experiments. The biosorption of both dyes followed better the pseudo-second order kinetic model. The calculated values for ?G, ?S, and ?H indicated that the biosorption of CR and MB onto the waste pretreated biomass was feasible, spontaneous, and exothermic in the selected temperature range and conditions.


2013 ◽  
Vol 16 (1) ◽  
pp. 22-31
Author(s):  
Phung Thi Kim Le ◽  
Kien Anh Le

Agricultural wastes are considered to be a very important feedstock for activated carbon production as they are renewable sources and low cost materials. This study present the optimize conditions for preparation of durian peel activated carbon (DPAC) for removal of methylene blue (MB) from synthetic effluents. The effects of carbonization temperature (from 673K to 923K) and impregnation ratio (from 0.2 to 1.0) with potassium hydroxide KOH on the yield, surface area and the dye adsorbed capacity of the activated carbons were investigated. The dye removal capacity was evaluated with methylene blue. In comparison with the commercial grade carbons, the activated carbons from durian peel showed considerably higher surface area especially in the suitable temperate and impregnation ratio of activated carbon production. Methylene blue removal capacity appeared to be comparable to commercial products; it shows the potential of durian peel as a biomass source to produce adsorbents for waste water treatment and other application. Optimize condition for preparation of DPAC determined by using response surface methodology was at temperature 760 K and IR 1.0 which resulted the yield (51%), surface area (786 m2/g), and MB removal (172 mg/g).


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