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In this work, filamentous algae-based activated carbon was composited with Fe3O4 nanoparticles and applied as a potential adsorbent to remove Basic Blue 41. AAC/Fe3O4 nanocomposite was synthesised by the impregnation method and characterised by several techniques including, FTIR, FESEM, EDX, TGA, XRD, VSM, and BET. The characterisation results confirmed the existence of Fe3O4 in the nanocomposite structure, which had uniformly dispersed over AAC with mesoporous texture. The effects of various operational parameters on removal efficiency were investigated. The maximum AAC/Fe3O4 nanocomposite adsorption capacity (141 mg g−1) and removal rate (96.76%) were determined under optimum conditions (initial concentration of 100 mg L−1, solution pH of 9, nanocomposite dose = 1 g L−1 at 25°C for 90 min). The obtained adsorption data fitted well with the pseudo-second-order Langmuir isotherm model. The reusability assessment of AAC/Fe3O4 nanocomposite (with acidic solution) revealed about 11% decreases in the removal efficiency after five consecutive runs. Finally, bioassay studies using D. Magna confirmed AAC/Fe3O4 nanocomposite could create low toxicity and acceptable quality effluents. These attractive features make it a potential adsorbent for practical application in actual textile wastewater treatment. [ABSTRACT FROM AUTHOR]

The aim of this study was to synthesize activated carbon from low-cost material and then magnetize it with CoFe2O4 nanoparticles for evaluating its efficiency in the removal of cephalexin from aqueous media. The physical and structural properties of the synthesized adsorbent were analyzed by SEM, BET, XRD, and VSM techniques. In addition, the effect of parameters, including pH, the concentration of cephalexin, adsorbent dose, and contact time, were studied to determine the equilibrium adsorption process isotherms and kinetics. The results of this study showed that the removal efficiency of cephalexin increases with increasing contact time and adsorbent dose and decreases with increasing pH and the initial concentration of cephalexin. As the concentration of antibiotics increased from 50 to 250 mg/L, the removal efficiency of cephalexin decreased from 96.8% to 36.1%. Optimal conditions for cephalexin removal were obtained at pH = 3, time = 30 min, antibiotics concentration = 50 mg/L, and adsorbent dose = 2 g/L. Cephalexin antibiotic adsorption process follows the Freundlich isotherm (R2 = 0.9817) and pseudo second-order kinetics (R2 = 0.939). Although the removal of cephalexin increases with increasing adsorbent dose, the amount of cephalexin adsorbed per unit mass of adsorbent (qe) decreases from 27.5 to 18.3 mg/g from 0.25 to 2.5 g/L of activated carbon. The present study showed that magnetized low-cost material activated carbon, in addition to having properties such as rapid and easy separation, has a high potential for cephalexin adsorption. [ABSTRACT FROM AUTHOR]

Treatment of colored wastewater is one of the important challenges of environmental engineers. Adsorption is one of the most efficient methods in dye removal. The aim of this study was to prepare a magnetic adsorbent with Fe3O4 nanoparticles as an inexpensive adsorbent to remove basic violet 16 (BV16) dye from aqueous media. In this experimental study, the effect of parameters such as initial solution pH, adsorbent dose, initial dye concentration, and contact time on the adsorption rate was investigated. The residual dye concentration was read at 545 nm by using a spectrophotometer. Physical, surface, and magnetic properties of the adsorbent were analyzed using Brunauer–Emmett–Teller (BET), Vibrating-Sample Magnetometer (VSM), X-ray Powder Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning electron microscope (SEM) techniques. Adsorption data were described by Langmuir and Freundlich isotherms and reaction kinetics. The results showed that with increasing the contact time and increasing the adsorbent dose, the amount of dye removal by the adsorbent increased and with decreasing the initial concentration of dye, the amount of removal increased. The results also showed that with increasing pH, the removal efficiency of the process increased linearly. According to resuls, the highest BV16 dye adsorption efficiency was 99%, which was obtained at determined values of studied parameters including pH of 7, adsorbent dose: of 0.5 g/L, initial BV16 dye concentration of 25 mg/l, mixing speed of 250 rpm, and contact time of 45 min. Moreover, according to results, removal of BV16 dye using adsorption onto clinoptilolite zeolite magnetized with Fe3O4 nanoparticles obey a second-order kinetic model and Freundlich model (R2>0.99). According to SEM images, the adsorbent surface used is non-uniform and has many pores and also the morphology of the adsorbent surface is preserved after loading of Fe3O4 nanoparticles. According to VSM images, the magnetic saturation in composite is 18.11 emu/g. Results hihlighted the adsorption of BV16 dye onto clinoptilolite zeolite magnetized with Fe3O4 nanoparticles was a useful technique and could provide high efficiency in removal of studied dye from aqueous solutionsl; thus, it mabe be effective and useful in removal other similar pollutants. [ABSTRACT FROM AUTHOR]

The natural organic matter in water resources poses many problems, such as unpleasant taste and colour in the water, and is one of the most important precursors to the formation of disinfection byproducts (DBPs) during water treatment. This study was performed to evaluate the efficiency of activated carbon (AC) and activated carbon coated with nZVI nanoparticles (AC-nZVI) to remove humic acid from aqueous solutions. To end this, the effect of some operational factors including pH, contact time, humic acid concentration and adsorbent dose was studied in removal of humic acid from aqueous solutions in the presence of AC and AC-nZVI. The structure of the adsorbents and their morphology were characterized by FTIR, BET, SEM and XRD analyzes. The adsorption isotherm was determined using Langmuir, Freundlich and kinetic adsorption models by studying quasi-first-order and quasi-second-order models. The thermodynamic parameters of the adsorption system such as changes in enthalpy (ΔH0), entropy (ΔS0) and free energy of Gibbs (ΔG0) were also measured and evaluated. The results showed that the removal efficiency is directly associated with the dose of adsorbent and has a reverse association with pH and humic acid concentration. The optimal removal of humic acid at the adsorbent dosage of 1.6 g/L, the humic acid concentration of 50 mg/L and the contact time of 45 min was found 84.7% and 95.68% for AC and AC-nZVI, respectively. The SBET and total pure volume for the AC-nZVI were 821.52 m2/g and 0.631 cm3/g respectively. The removal rate by AC-nZVI as significantly high, indicating the effective role of nanoparticle stabilisation on activated carbon. As a result, it is possible to find an effective and highly efficient adsorbent by stabilising the nanoparticles on activated carbon that can be used to remove humic acid. [ABSTRACT FROM AUTHOR]

Huge quantities of different dyes are generated by various industries such as cosmetic, leather, printing and textile and food. This study aimed to generate and apply tire-derived activated carbon magnetised with the Fe3O4 nanoparticles (MAC) for the removal of reactive blue 19 (RB19) dye from aquatic solutions. FE-SEM, VSM, XRD, FTIR and BET analyses were used to determine MAC properties. Under optimal conditions of pH 3, the initial concentration of dye 100 mg/L, the composite dose 1 g/L and the reaction time of 45 min, the removal efficiency for RB19 was 93.22%. Isotherm findings illustrated that RB19 adsorption onto the MAC followed the Langmuir model. Moreover, the absorption kinetics is well interpreted by the pseudo-second-order model in low scrutinised concentrations. The SBET and total pure volume for the MAC were 421.11 m2 g−1 and 0.467 cm3 g−1. Under the optimum conditions, maximum adsorption capacity of the MAC in Langmuir model enhanced to the amount of 119.05 mg/g. Also, the reusability (with NaOH) of the MAC revealed about 21% decreases in the removal efficiency within five consecutive runs. It is concluded that the application of the magnetised activated carbon due to its high efficiency in removing RB19 from laboratory and actual samples can be evaluated in future studies to be utilised in real scales. [ABSTRACT FROM AUTHOR]

Cationic dyes are one of the aromatic compounds that cause major environmental problems. The adsorption process has attracted a lot of attention in recent years. In this study, the seeds were used as a low-cost adsorbent for the removal of cationic Blue 41 dye from aquatic environments. The studied parameters included the effect of adsorbent dosage, pH of the solution, contact time, and the initial concentration of Cationic Blue 41 dye. The removal efficiency in optimal conditions for Cationic Blue 41 with Salvia seeds (concentration = 50 mg/L, dose = 2 g/L, reaction time = 120 min and pH = 9) was obtained 70%. The data were evaluated using Freundlich and Langmuir methods. The structure and characteristics of the seeds were determined by Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FT-IR) and Brunauer-Emmett-Teller (BET) techniques. The SBET and total pure volume for the Salvia seeds were 3.053 m2/g and 0.684 cm3/g. The results showed that the adsorption process follows Langmuir model with an adsorption capacity of 19.16 mg/g. According to the result of the pseudo-first and pseudo-second kinetic study, it was found that the process of dye adsorption on the low-cost seeds best described by pseudo-second kinetic. The findings showed that the Salvia seeds can be used as a natural absorbent, environmentally friendly and affordable treatment for water and wastewater, especially those containing cationic dyes. [ABSTRACT FROM AUTHOR]

Drainage of untreated wastewater from the textile industry due to the use of toxic compounds in it causes pollution in aquatic environments and major environmental and health problems. Therefore, the aim of the present study is to compare the performance of activated carbon coated with AC-ZnO composite as an adsorbent to remove the AB-113 from the aqueous solution. The present study is an experimental-laboratory study in which the effect of independent parameters has been investigated. FTIR and XRD analyzes were performed to determine the composition of the composite. Isothermal and kinetic adsorption at different concentrations were evaluated to evaluate the process. The results of physical-chemical analysis confirmed the correctness of the composite structure. Optimal conditions for AB-113 (with a concentration of 100 mg/L, a composite dose of 0.5 g/L, a reaction time of 15 minutes and pH = 3) 98.2% were obtained. The results of the study of isothermal and kinetic adsorption for dye showed that the adsorption process follows the isotherm of Freundlich (R2 = 0.9859) and Pseudo-second-order. The maximum adsorption capacity of AC-ZnO composite was determined using Langmuir model 333.33 mg/g. Thermodynamic parameters showed the non-spontaneity and endothermic in nature of adsorption process. The present study showed that nanoparticle stabilization technology can be used on activated carbon as an effective and efficient adsorbent to remove dye from aqueous solutions. [ABSTRACT FROM AUTHOR]

The adsorption techniques are extensively used in dyes, metronidazole, aniline, wastewater treatment methods to remove certain pollutants. Furfural is organic in nature, considered a pollutant having a toxic effect on humans and their environment and especially aquatic species. Due to distinct characteristics of the adsorption technique, this technique can be utilized to adsorb furfural efficiently. As an environmentally friendly technique, the pomegranate peel was used to synthesized activated carbon and nanostructure of zerovalent iron impregnated on the synthesized activated carbon. The physicochemical and crystallinity characterization was done using Fourier transmission infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), and Field emission scanning electron microscopy (FESEM). The nanoparticles are porous in structure having 821.74 m 2 /g specified surface area. The maximum amount of the adsorbent pores in the range of 3.08 nm shows the microporous structure and enhancement in adsorption capacity. The effects of increment in concentration of adsorbent, pH, reaction contact time and adsorbent dose, isothermal and kinetic behaviour were investigated. At the UV wavelength of 227 nm furfural adsorption was detected. The separation of the furfural from the aqueous solution was calculated at the 1 h reaction time at the composite dosage of 4 g/L, 250 mg/L adsorbent concentration and pH kept at 7. The 81.87% is the maximum removal attained by the nanocomposite in comparison to the activated carbon is 62.06%. Furfural adsorption was also analyzed by using the equations of isothermal and kinetics models. The adsorption process analysis depends on the Freundlich isotherm and Intra-particle diffusion than the other models. The maximum adsorbent of the composite was determined by the Langmuir model which is 222.22 mg/g. The furfural removal enhances as the adsorbent dose enhances. The developed zerovalent iron nanoparticles incorporated on activated carbon (AC/nZVI) from pomegranate peel extract are feasible as an efficient and inexpensive adsorbent to eliminate furfural from a liquid solution., (Copyright © 2021 Elsevier Ltd. All rights reserved.)