Magnetic and electrical-assisted adsorption processes

Clean water is a vital need for all living creatures during their lifespan. However, contaminated stormwater is a major issue around the globe. A wide range of contaminants, including heavy metals, organic and inorganic impurities, has been discovered in stormwater. Some commonly utilized methods, such as biological, physical and chemical procedures, have been considered to overcome these issues. However, these current approaches result in moderate to low contaminant removal efficiencies for certain classes of contaminants. Of late, filtration and adsorption processes have become more featured in permeable concretes (PCs) for the treatment of stormwater. As nanoparticles have vast potential and unique characterizations, such as a higher surface area to cure polluted stormwater, employing them to improve permeable concretes’ capabilities in stormwater treatment systems is an effective way to increase filtration and adsorption mechanisms. The present study reviews the removal rate of different stormwater contaminants such as heavy metals, organic and other pollutants using nanoparticle-improved PC. The application of different kinds of nanomaterials in PC as porous media to investigate their influences on the properties of PC, including the permeability rate, compressive strength, adsorption capacity and mix design of such concrete, was also studied. The findings of this review show that different types of nanomaterials improve the removal efficiency, compressive strength and adsorption capacity and decrease the infiltration rate of PC during the stormwater treatment process. With regard to the lack of comprehensive investigation concerning the use of nanomaterials in PC to treat polluted stormwater runoff, this study reviews 242 published articles on the removal rate of different stormwater contaminants by using PC improved with nanoparticles.

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Effective Magnetic MOFs Adsorbent for the Removal of Bisphenol A, Tetracycline, Congo Red and Methylene Blue Pollutions

Nanomaterials ◽

10.3390/nano11081917 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1917

Author(s):

Guangpu Zhang ◽

Rong Wo ◽

Zhe Sun ◽

Gazi Hao ◽

Guigao Liu ◽

...

Keyword(s):

Methylene Blue ◽

Electron Microscope ◽

Bisphenol A ◽

Congo Red ◽

Reduction Process ◽

Entropy Change ◽

Potential Candidate ◽

Order Kinetic ◽

Adsorption Processes ◽

Infrared Spectrometer

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.

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Ideal pH for the adsorption of metal ions Cr6+, Ni2+, Pb2+ in aqueous solution with different adsorbent materials

Open Agriculture ◽

10.1515/opag-2021-0225 ◽

2021 ◽

Vol 6 (1) ◽

pp. 115-123

Author(s):

Luísa P. Cruz-Lopes ◽

Morgana Macena ◽

Bruno Esteves ◽

Raquel P. F. Guiné

Keyword(s):

Heavy Metals ◽

Metal Ions ◽

Walnut Shell ◽

Lead Adsorption ◽

Viable Solution ◽

Chestnut Shell ◽

Adsorption Processes ◽

Irreversible Effects ◽

Optimal Values ◽

Ph Range

Abstract Industrialization increases the number of heavy metals released into the environment. Lead (Pb2+), nickel (Ni2+) and chromium (Cr6+) are among these toxic metals and cause irreversible effects on ecosystems and human health due to their bio-accumulative potential. The decontamination through adsorption processes using lignocellulosic wastes from agricultural and/or forestry processes is a viable solution. Hence, this work aimed at studying the effect of pH on the biosorption of the metal ions using four different by-product materials: walnut shell, chestnut shell, pinewood and burnt pinewood. These experiments were conducted with solutions of the three heavy metals in which the adsorbents were immersed to measure the rate of adsorption. A range of pH values from 3.0 to 7.5 was used in the experiments, and the concentrations were determined by atomic absorption. The results showed different behaviour of the biosorbent materials when applied to the different metals. The lead adsorption had an ideal pH in the range of 5.5–7.5 when the walnut shell was used as an adsorbent, corresponding to values of adsorption greater than 90%, but for the other materials, maximum adsorption occurred for a pH of 7.5. For the adsorption of chromium, the pH was very heterogeneous with all adsorbents, with optimal values of pH varying from 3.0 (for chestnut shell) to 6.5 (for walnut shell and wood). For nickel, the best pH range was around pH 5, with different values according to the lignocellulosic material used. These results indicate that the tested biosorbents have the potential to decontaminate wastewater in variable extensions and that by controlling the pH of the solution; a more efficient removal of the heavy metals can be achieved.

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Experimental investigation into the integration of solid desiccant packed beds with oscillating heat pipes for energy efficient isothermal adsorption processes

Thermal Science and Engineering Progress ◽

10.1016/j.tsep.2020.100791 ◽

2021 ◽

Vol 21 ◽

pp. 100791

Author(s):

S.K. Yeboah ◽

J. Darkwa

Keyword(s):

Experimental Investigation ◽

Energy Efficient ◽

Heat Pipes ◽

Packed Beds ◽

Isothermal Adsorption ◽

Adsorption Processes

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Synthesis and characterization of Cu(OH)2-NWs-PVA-AC Nano-composite and its use as an efficient adsorbent for removal of methylene blue

Scientific Reports ◽

10.1038/s41598-021-84797-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sivarama Krishna Lakkaboyana ◽

Khantong Soontarapa ◽

Nabel Kalel Asmel ◽

Vinay Kumar ◽

Ravi Kumar Marella ◽

...

Keyword(s):

Methylene Blue ◽

Kinetic Models ◽

Batch Reactor ◽

Maximum Adsorption Capacity ◽

Nano Composite ◽

Adsorption Processes ◽

Intra Particle Diffusion ◽

Short Time ◽

Efficient Adsorbent

AbstractThe present study focused on the synthesis of copper hydroxide nanowires decorated on activated carbon (Cu(OH)2-NWs-PVA-AC). The obtained Cu(OH)2-NWs-PVA-AC Nano-composite was distinguished by XRD, SEM, EDX, BET, FTIR and XPS respectively. Besides, different variables such as solution pH, and initial dye concentration, contact time, and temperature were performed on the adsorption efficiency of MB in a small batch reactor. Further, the experimental results are analyzed by various kinetic models via PFO, PSO, intra-particle diffusion and Elovich models, and the results revealed that among the kinetic models, PSO shows more suitability. In addition, different adsorption isotherms were applied to the obtained experimental data and found that Langmuir–Freundlich and Langmuir isotherm were best fits with the maximum adsorption capacity of 139.9 and 107.6 mg/g, respectively. The Nano-composite has outstanding MB removal efficiency of 94–98.5% with a span of 10 min. and decent adsorption of about 98.5% at a pH of 10. Thermodynamic constants like Gibbs free energy, entropy, and enthalpy were analyzed from the temperature reliance. The results reveal the adsorption processes are spontaneous and exothermic in nature. The high negative value of ΔG° (− 44.11 to − 48.86 kJ/mol) and a low negative value of ΔH° (− 28.96 kJ/mol) show the feasibility and exothermic nature of the adsorption process. The synthesized dye was found to be an efficient adsorbent for the potential removal of cationic dye (methylene blue) from wastewater within a short time.

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Removal of Chromium(III) and Cadmium(II) Heavy Metal Ions from Aqueous Solutions Using Treated Date Seeds: An Eco-Friendly Method

Molecules ◽

10.3390/molecules26123718 ◽

2021 ◽

Vol 26 (12) ◽

pp. 3718

Author(s):

Mohammad Azam ◽

Saikh Mohammad Wabaidur ◽

Mohammad Rizwan Khan ◽

Saud I. Al-Resayes ◽

Mohammad Shahidul Islam

Keyword(s):

Metal Ions ◽

Adsorption Capacity ◽

Low Cost ◽

Maximum Adsorption Capacity ◽

Solution Ph ◽

Surface Analysis Techniques ◽

Adsorption Processes ◽

Ft Ir ◽

Metal Elution ◽

Date Pits

The aim of the research was to prepare low-cost adsorbents, including raw date pits and chemically treated date pits, and to apply these materials to investigate the adsorption behavior of Cr(III) and Cd(II) ions from wastewater. The prepared materials were characterized using SEM, FT-IR and BET surface analysis techniques for investigating the surface morphology, particle size, pore size and surface functionalities of the materials. A series of adsorption processes was conducted in a batch system and optimized by investigating various parameters such as solution pH, contact time, initial metal concentrations and adsorbent dosage. The optimum pH for achieving maximum adsorption capacity was found to be approximately 7.8. The determination of metal ions was conducted using atomic adsorption spectrometry. The experimental results were fitted using isotherm Langmuir and Freundlich equations, and maximum monolayer adsorption capacities for Cr(III) and Cd(II) at 323 K were 1428.5 and 1302.0 mg/g (treated majdool date pits adsorbent) and 1228.5 and 1182.0 mg/g (treated sagai date pits adsorbent), respectively. It was found that the adsorption capacity of H2O2-treated date pits was higher than that of untreated DP. Recovery studies showed maximal metal elution with 0.1 M HCl for all the adsorbents. An 83.3–88.2% and 81.8–86.8% drop in Cr(III) and Cd(II) adsorption, respectively, were found after the five regeneration cycles. The results showed that the Langmuir model gave slightly better results than the Freundlich model for the untreated and treated date pits. Hence, the results demonstrated that the prepared materials could be a low-cost and eco-friendly choice for the remediation of Cr(III) and Cd(II) contaminants from an aqueous solution.

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