High Exposure Effect of the Adsorption Site Significantly Enhanced the Adsorption Capacity and Removal Rate: A Case of Adsorption of Hexavalent Chromium by Quaternary Ammonium Polymers (QAPs)

2021 ◽  
pp. 125829
Author(s):  
Lili Fang ◽  
Lin Ding ◽  
Wei Ren ◽  
Huiqin Hu ◽  
Yong Huang ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Hexavalent Chromium ◽  
Quaternary Ammonium ◽  
Removal Rate ◽  
Adsorption Site ◽  
High Exposure ◽  
Exposure Effect

The Preparation and Phosphate Adsorption Experiments of New Modified Bamboo Powder

2014 ◽  
Vol 1081 ◽  
pp. 20-24 ◽  
Author(s):  
Ting He ◽  
Xin Li ◽  
Yun Gong
Keyword(s):  
Adsorption Capacity ◽  
Quaternary Ammonium ◽  
Removal Rate ◽  
Model Fitting ◽  
Raw Material ◽  
Phosphate Adsorption ◽  
Element Analysis ◽  
Adsorption Effect ◽  
Initial Concentration ◽  
Bamboo Powder

The bamboo processing residues, as raw material, was modified by quaternary ammonium to obtain a quaternary ammonium modified bamboo powder adsorbent. The phosphate’s adsorption capacity of the powder adsorbent was investigated. In addition, the effects of dosage, pH, time, temperature, initial concentration on phosphate’s adsorption capacity. Then, the research performed the adsorption isotherm model fitting. The results showed that the adsorption rate of modified bamboo powder to phosphate increased with increase of dosing amount of modified bamboo powder, tended to be equilibrium when the removal rate reached to 97%; while the phosphate with high initial concentration could improve the adsorption capacity of modified bamboo powder. In acidic condition, the modified bamboo powder presented unsatisfied adsorption effect on phosphate, when pH= 6 the adsorption effect become well, but adsorption effect did not vary apparently with the increase of pH. With the increase of temperature (25, 35, 45°C), the maximum saturated adsorption capacity of modified bamboo powder gradually reduced. The adsorption of modified bamboo powder on phosphate was a rapid process, which could reach equilibrium status within 50 minutes. The bamboo powder before and after the modification was conducted IR element analysis, the values before modification are N=0, C=45.54 and H=6.03; while after the modification, the values are N=2.65, C=40.33 and H=6.79, it is concluded that the nitrogen content of modified bamboo powder increase obviously and the quaternary ammonium can well be grafted.

scholarly journals Stormwater Runoff Treatment Using Pervious Concrete Modified with Various Nanomaterials: A Comprehensive Review

2021 ◽  
Vol 13 (15) ◽  
pp. 8552
Author(s):  
Vahid Alimohammadi ◽  
Mehdi Maghfouri ◽  
Delaram Nourmohammadi ◽  
Pejman Azarsa ◽  
Rishi Gupta ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Compressive Strength ◽  
Adsorption Capacity ◽  
Removal Rate ◽  
Stormwater Runoff ◽  
Infiltration Rate ◽  
Stormwater Treatment ◽  
Adsorption Mechanisms ◽  
Wide Range ◽  
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.

scholarly journals Hydrothermal Synthesis of Sodalite-Type N-A-S-H from Fly Ash to Remove Ammonium and Phosphorus from Water

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2741
Author(s):  
Pengcheng Lv ◽  
Ruihong Meng ◽  
Zhongyang Mao ◽  
Min Deng
Keyword(s):  
Fly Ash ◽  
Adsorption Capacity ◽  
Removal Rate ◽  
Kinetic Studies ◽  
Solute Concentration ◽  
Raw Material ◽  
Sodium Aluminosilicate ◽  
Equilibrium Data ◽  
One Step ◽  
Ft Ir

In this study, the hydrated sodium aluminosilicate material was synthesized by one-step hydrothermal alkaline desilication using fly ash (FA) as raw material. The synthesized materials were characterized by XRD, XRF, FT-IR and SEM. The characterization results showed that the alkali-soluble desilication successfully had synthesized the sodium aluminosilicate crystalline (N-A-S-H) phase of sodalite-type (SOD), and the modified material had good ionic affinity and adsorption capacity. In order to figure out the suitability of SOD as an adsorbent for the removal of ammonium and phosphorus from wastewater, the effects of material dosing, contact time, ambient pH and initial solute concentration on the simultaneous removal of ammonium and phosphorus are investigated by intermittent adsorption tests. Under the optimal adsorption conditions, the removal rate of ammonium was 73.3%, the removal rate of phosphate was 85.8% and the unit adsorption capacity reached 9.15 mg/L and 2.14 mg/L, respectively. Adsorption kinetic studies showed that the adsorption of ammonium and phosphorus by SOD was consistent with a quasi-secondary kinetic model. The adsorption isotherm analysis showed that the equilibrium data were in good agreement with the Langmuir and Freundlich model. According to thermodynamic calculations, the adsorption of ammonium and phosphorus was found to be a heat-absorbing and spontaneous process. Therefore, the preparation of SOD by modified FA has good adsorption properties as adsorbent and has excellent potential for application in the removal of contaminants from wastewater.

Experimental and kinetic analysis of hydrothermal aging effects on ammonia adsorption capacity over a commercial Cu-zeolite selective catalytic reduction catalyst

2018 ◽  
Vol 233 (12) ◽  
pp. 3030-3042
Author(s):  
Tae Joong Wang ◽  
In Hyuk Im
Keyword(s):  
Adsorption Capacity ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Adsorption Site ◽  
Selective Catalytic Reduction Catalyst ◽  
Aging Effects ◽  
Hydrothermal Aging ◽  
Ammonia Adsorption ◽  
Fresh Catalyst ◽  
Reduction Catalysts

Ammonia/urea selective catalytic reduction is an efficient technology to control NOx emission from diesel engines. One of its critical challenges is the performance degradation of selective catalytic reduction catalysts due to the hydrothermal aging experienced in real-world operations during the lifetime. In this study, hydrothermal aging effects on the reduction of ammonia adsorption capacity over a commercial Cu-zeolite selective catalytic reduction catalyst were investigated under actual engine exhaust conditions. Ammonia adsorption site densities of the selective catalytic reduction catalysts aged at two different temperatures of 750°C and 850°C for 25 h with 10% H2O were experimentally measured and compared to that of fresh catalyst on a dynamometer test bench with a heavy-duty diesel engine. The test results revealed that hydrothermal aging significantly decreased the ammonia adsorption capacity of the current commercial Cu-zeolite selective catalytic reduction catalyst. Hydrothermal treatment at 750°C reduced the ammonia adsorption site to 62.5% level of that of fresh catalyst, while hydrothermal treatment at 850°C lowered the adsorption site to 37.0% level of that of fresh catalyst. Also, in this study, numerical simulation and kinetic analysis were carried out to quantify the impact of hydrothermal aging on the reduction of ammonia adsorption capacity by introducing an aging coefficient. The kinetic parameter calibrations based on actual diesel engine tests with a commercial monolith Cu-zeolite selective catalytic reduction catalyst provided a highly realistic kinetic parameter set of ammonia adsorption/desorption and enabled a mathematical description of hydrothermal aging effect.

scholarly journals Synthesis and characterization of thiol-polystyrene microsphere and its adsorption properties of thallium

2021 ◽  
Vol 237 ◽  
pp. 01001
Author(s):  
Youze Xu ◽  
Yuehui Chen ◽  
Yuanyuan Zhao ◽  
Shuang Zhou ◽  
Guangyi Fu ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Raw Materials ◽  
Removal Rate ◽  
Adsorption Properties ◽  
Membrane Diffusion ◽  
Polystyrene Microspheres ◽  
Polystyrene Microsphere ◽  
Control Step ◽  
Ft Ir ◽  
Modified Polystyrene

Thallium (Tl) is highly toxic in the environment. In order to solve the harm of Tl pollution to the environment, thiol-polystyrene microsphere (TPM) with good adsorption properties for Tl were prepared in this paper. The GAUSSIAN software was used to calculate the adsorption performance of the TPM on Tl+, and the adsorption mechanism was discussed. The thermogravimetric analysis show that the TPM prepared with chloromethyl polystyrene microspheres (CPM) and thiourea as the main raw materials has good chemical thermal stability. In the Tl+ solution of 1mg/L, the adsorption and removal rate of the TPMs in was 99%, with a significant adsorption of Tl+ properties. When the dosage of TPM is 0.4L/g, pH is 6-10, temperature is 5-20 °C, and adsorption time reaches 640min, thallium-containing water with Tl+ concentration of 5mg/L can be treated to within the national discharge standard (5μg/L). The analytical effect of 0.5mol/L dilute sulfuric acid on TPM can reach 99.96%, and the adsorption capacity of TPM on Tl+ is reduced by only 0.1% after repeated use 4 times, which has good regeneration performance. The modified polystyrene microspheres were characterized by EDS, FT-IR, Raman spectra and XPS, and it was proved that the TPM were ligated with Tl+ through the grafted mercapto group, so as to adsorb and remove Tl+ from the solution. According to the isotherm and kinetic model of TPM adsorption Tl+, the maximum saturated adsorption amount of TPM to Tl+ can reach 3.47mg/g, mainly chemical adsorption, and the membrane diffusion stage is the main control step of TPM adsorption Tl+. The results showed that the TPM could be a promising adsorbent with good adsorption capacity and reusability for Tl+ removal from wastewater

Nanoparticle Fe3O4 magnetized activated carbon from Armeniaca sibirica shell for the adsorption of Hg(II) ions

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 6100-6120
Author(s):  
Yinan Hao ◽  
Yanfei Pan ◽  
Qingwei Du ◽  
Xudong Li ◽  
Ximing Wang
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Ph Value ◽  
Removal Rate ◽  
Freundlich Isotherm ◽  
Entropy Change ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Adsorption Parameters ◽  
Initial Concentration

Armeniaca sibirica shell activated carbon (ASSAC) magnetized by nanoparticle Fe3O4 prepared from Armeniaca sibirica shell was investigated to determine its adsorption for Hg2+ from wastewater. Fe3O4/ASSAC was characterized using XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy), and BET (Brunauer–Emmett–Teller). Optimum adsorption parameters were determined based on the initial concentration of Hg2+, reaction time, reaction temperature, and pH value in adsorption studies. The experiment results demonstrated that the specific surface area of ASSAC decreased after magnetization; however the adsorption capacity and removal rate of Hg2+ increased 0.656 mg/g and 0.630%, respectively. When the initial concentration of Hg2+ solution was 250 mg/L and the pH value was 2, the adsorption time was 180 min and the temperature was 30 °C, and with the Fe3O4/ASSAC at 0.05 g, the adsorption reaching 97.1 mg/g, and the removal efficiency was 99.6%. The adsorption capacity of Fe3O4/ASSAC to Hg2+ was in accord with Freundlich isotherm models, and a pseudo-second-order kinetic equation was used to fit the adsorption best. The Gibbs free energy ΔGo < 0，enthalpy change ΔHo < 0, and entropy change ΔSo < 0 which manifested the adsorption was a spontaneous and exothermic process.

scholarly journals Synthesis and degradation kinetics of TiO2/GO composites with highly efficient activity for adsorption and photocatalytic degradation of MB

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ruifen Wang ◽  
Kaixuan Shi ◽  
Dong Huang ◽  
Jing Zhang ◽  
Shengli An
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Adsorption Capacity ◽  
Degradation Kinetics ◽  
Removal Rate ◽  
Strong Adsorption ◽  
Degradation Activity ◽  
Kinetics Of ◽  
Stacking Structure ◽  
Synthesis And Degradation

AbstractPoriferous TiO2/GO (denoted as TGO-x%) photocatalysts with ultrathin grapheme oxide (GO) layer were prepared by a hydrothermal method, the adsorption and photocatalytic degradation and its kinetics about Methylene blue(MB) were studied systematically. All the TGO-x% showed improved adsorption and photodegradation performance. TGO-25% had excellent adsorptivity while TGO-20% exhibit the highest visible light photocatalytic degradation activity. The adsorption capacity for TGO-25% was 20.25 mg/gcatalyst along with the k1 was about 0.03393 min·gcatalyst/mg, this enhancement was mainly owing to the strong adsorption capacity of GO and the stacking structure of sheets and nanoparticles. GO sheets prevented the agglomeration of TiO2 particles and TiO2 nanoparticles also prevented the agglomeration of GO sheets, which could provides greater surface area. Besides, the remarkably superior photodegradation activity of TiO2/GO composites is mainly attribute to the strong absorption of visible light and the effective charge separation revealed by the photoluminescence, the total removal rate of MB is 97.5% after 35 min adsorption and 140 min degradation, which is 3.5 times higher than that of TiO2.

scholarly journals Preparation of grafting copolymer of acrylic acid onto loess surface and its adsorption behavior

2020 ◽  
Vol 82 (4) ◽  
pp. 673-682
Author(s):  
Fengqin Tang ◽  
Di Gao ◽  
Li Wang ◽  
Yufeng He ◽  
Pengfei Song ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Adsorption Capacity ◽  
Removal Rate ◽  
Vinyl Pyrrolidone ◽  
Mineral Particle ◽  
Gravimetric Analysis ◽  
Order Kinetic ◽  
Experimental Conditions ◽  
Order Kinetic Model ◽  
Grafting Copolymer

Abstract Loess is a typical natural mineral particle distributed widely around the world, and it is inexpensive, readily accessible, and harmless to the environment. In this study, loess was modified by surface grafting copolymerization of functional monomers, such as acrylic acid, N-vinyl pyrrolidone, and N,N-methylenebisacrylamide as a cross-linking agent, which afforded a novel loess-based grafting copolymer (LC-PAVP). After being characterized by scanning electron microscopy, thermal gravimetric analysis and Fourier-transform infrared spectroscopy, its adsorption capacity and mechanism of removing lead ions (Pb2+) were investigated. With the study of the optimal experimental conditions, it was demonstrated that the removal rate of Pb2+ by LC-PAVP can reach up to 99.49% in 60 min at room temperature. It was also found that the kinetic characteristics of the adsorption capacity due to the pseudo-second-order kinetic model and the thermodynamics conformed well with the Freundlich model. In summary, as a lost-cost and eco-friendly loess-based adsorbent, LC-PAVP is a good potential material for wastewater treatment.

Improved adsorption of Congo red by nanostructured flower-like Fe(II)–Fe(III) hydroxy complex

2018 ◽  
Vol 78 (3) ◽  
pp. 506-514
Author(s):  
Xiaoyan Sun ◽  
Zhongwu Liu ◽  
Zhigang Zheng ◽  
Hongya Yu ◽  
Dechang Zeng
Keyword(s):  
Adsorption Capacity ◽  
Anion Exchange ◽  
Electrostatic Interaction ◽  
Congo Red ◽  
Removal Rate ◽  
Superior Performance ◽  
Facile Synthesis ◽  
Similar Reduction ◽  
Microwave Assisted ◽  
Strong Adsorption

Abstract Amorphous Fe(II)–Fe(III) hydroxy complex with flower-like nanostructure was synthesized by ferric reduction using a microwave-assisted ethylene glycol approach. Here we investigated the correlation between its chemical composition and the removal rate for Congo red (CR) dye. The results showed that the amorphous complex had similar reduction and anion exchange capacities to the green rust. Due to the synergistic effect of attractive electrostatic interaction, anion exchange, ferrous redox and hydrogen bonding, the Fe(II)–Fe(III) hydroxy complex exhibited strong adsorption of CR with an estimated adsorption capacity up to 513 mg g−1. In contrast, the Fe(III) hydroxy complex had an adsorption capacity of 296 mg g−1 because of the predominant mechanism based on the electrostatic interaction. The present study provides a facile synthesis of nanostructured iron hydroxy complex, with superior performance in adsorbing CR.

Optimization of the Adsorption Condition for Wastewater Containing Chromium Treatment by Natural Adsorbent Material Using Response Surface Methodology

2014 ◽  
Vol 1033-1034 ◽  
pp. 387-390
Author(s):  
Ya Jun Wang ◽  
Jin Xi Wang ◽  
Yan Juan Li ◽  
Ying Wang
Keyword(s):  
Response Surface ◽  
Hexavalent Chromium ◽  
Removal Rate ◽  
Potassium Chromate ◽  
Optimal Experimental Design ◽  
Quadratic Model ◽  
Optimal Conditions ◽  
Optimal Parameters ◽  
Surface Method ◽  
Adsorption Condition

The effect of several important parameters on the removal of hexavalent chromium by humic acid was evaluated using an optimal experimental design based on Box-Behnken Response Surface method. The factors included temperature、pH、initial potassium chromate concentration and adsorbent dosage. A quadratic model for predicting the optimum removal conditions was derived, and the obtained optimal parameters were temperature 51°C, pH=2.34, initial potassium chromate concentration 14.30mg/L and adsorbent 0.58g. At the optimal conditions, the maximal removal rate of hexavalent chromium reached 73.17 %( forecast value was 73.26%).

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