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

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.

2021 ◽  
Vol 237 ◽  
pp. 01001
Author(s):  
Youze Xu ◽  
Yuehui Chen ◽  
Yuanyuan Zhao ◽  
Shuang Zhou ◽  
Guangyi Fu ◽  
...  

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


Author(s):  
Qingqing Liu ◽  
Xiaoyan Li

The activated MgO was synthesized by microwave homo-precipitator method and characterized by SEM, EDS and FT-IR methods. It was used to adsorption of U(VI) from aqueous solution with batch system. The paper discussed the effect of pH, temperature, contact time, adsorbent dose and initial U(VI) concentration on the adsorption. The results showed that activated MgO has good adsorption capacity for U(VI), the removal rate and equilibrium adsorption capacity reached 83.5% and 84.04mg·g−1 at pH 5.0, 15mg dose and 313K,respectively. The adsorption kinetics of U(VI) onto activated MgO were better fitted with pseudo-second-order kinetic.The adsorption isotherm data were fitted well to Freundlich isotherm model.The thermodynamic parameters showed that the adsorption process is endothermic and spontaneous.


2011 ◽  
Vol 80-81 ◽  
pp. 298-301
Author(s):  
Shi Wei Cao ◽  
Wei Chen ◽  
Zhao Qian Jing

Fly ash Ceramsite, Artificial Biofilter Bed, Dry Umbrella Bamboo, Phosphorus Removal Abstract: High calcium fly ash ceramsite had tremendous surface area and porosity, the unit weight of fly ash adsorption column adsorption capacity of ceramsite was 0.032mg•g-1, which was higher than normal calcium fly ash ceramsite adsorption capacity. The fix adsorption column tests showed that the adsorption capacity got stable when the contact time was 3 hours and the saturation adsorption was got at the ninth hour. The result of subsequent tests showed that the phosphorus resolve would not occur if the adsorption condition doesn’t change. The pilot test with actual wastewater was done and the results showed that the PO43- concentrations of effluent were less than 0.2mg•L-1 and the removal rate reached 90%, dry umbrella bamboo was the most suitable aquatic plant. The artificial biological filter process monitoring showed that the phosphorus of the sewage was mainly removed in the front of artificial biological filter bed.


2021 ◽  
Author(s):  
Wende Zhao ◽  
Liping Chen

Abstract In this work, sunflower straw (SS) was used as the raw material, H3PO4 was used as the activator, and the sunflower straw activated carbon (SSAC) was prepared by the one-step activation method under the impregnation ratio of 1:1, 1:2, 1:3, 1:5 (SS/H3PO4, g/g). The adsorption of acid fuchsin (AF) simulated dye wastewater by SSAC prepared under different immersion ratios has been studied. As the impregnation ratio increases, the pore structures of SSAC changed greatly. SSAC3 had the largest specific surface area (1794.01 m2/g), and SSAC4 had the smallest microporosity (0.0527 cm3/g) and the largest pore volume (2.549 cm3/g). The adsorption kinetics of four types of SSAC to AF were more in line with the quasi-second-order adsorption kinetic model. The Langmuir isotherm model was suitable for describing SSAC3 and SSAC4, and the Freundlich isotherm model was suitable for describing SSAC1 and SSAC2. Thermodynamics showed that the adsorption process was spontaneous and endothermic. At 303 K, SSAC4 showed a removal rate of 97.73% for 200 mg/L AF, and the maximum adsorption capacity of 2763.36 mg/g, which was the highest among the four types of SSAC. This study shows that the sunflower straw activated carbon prepared by the H3PO4 one-step activation method is a green and efficient carbon material and has great application potential in the treatment of dye-containing wastewater.


Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 962
Author(s):  
Kuo-Yu Chen ◽  
Wei-Yu Zeng

Poly-γ-glutamate/apatite (PGA-AP) nanoparticles were prepared by chemical coprecipitation method in the presence of various concentrations of poly-γ-glutamate (γ-PGA). Powder X-ray diffraction pattern and energy-dispersive spectroscopy revealed that the main crystal phase of PGA-AP was hydroxyapatite. The immobilization of γ-PGA on PGA-AP was confirmed by Fourier transform infrared spectroscopy and the relative amount of γ-PGA incorporation into PGA-AP was determined by thermal gravimetric analysis. Dynamic light scattering measurements indicated that the particle size of PGA-AP nanoparticles increased remarkably with the decrease of γ-PGA content. The adsorption of aqueous Cu(II) onto the PGA-AP nanoparticles was investigated in batch experiments with varying contact time, solution pH and temperature. Results illustrated that the adsorption of Cu(II) was very rapid during the initial adsorption period. The adsorption capacity of PGA-AP nanoparticles for Cu(II) was increased with the increase in the γ-PGA content, solution pH and temperature. At a pH of 6 and 60 °C, a higher equilibrium adsorption capacity of about 74.80 mg/g was obtained. The kinetic studies indicated that Cu(II) adsorption onto PGA-AP nanoparticles obeyed well the pseudo-second order model. The Langmuir isotherm model was fitted well to the adsorption equilibrium data. The results indicated that the adsorption behavior of PGA-AP nanoparticles for Cu(II) was mainly a monolayer chemical adsorption process. The maximum adsorption capacity of PGA-AP nanoparticles was estimated to be 78.99 mg/g.


Author(s):  
Yaping Zhang ◽  
Di Gao ◽  
Yufeng He ◽  
Bozhen Li ◽  
Pengfei Song ◽  
...  

Abstract The attapulgite (APT), a typical nano-rod structured clay was introduced to MIL-101(Fe), a typical eco-friendly iron-based Metal-Organic Framework material (MOF), during the preparation by a one-step solvothermal method, which afforded a novel APT and MOF hybrid (APT@MIL). Based on the characterization of SEM, FT-IR and XRD, it was found that the rod-like crystals of APT determined the size of MIL-101(Fe) while maintaining its regular octahedral crystal form, and the crystal size of MIL-101(Fe) in APT@MIL enlarged 4 times. It was also discovered that the rod-like APT were evenly distributed in MIL-101(Fe) crystals. Using APT@MIL as the photocatalyst, some organic dyes were photodegraded in simulated sunlight. The analysis indicated that APT@MIL has high adsorption and photodegradation activity, the removal rate of methylene blue was up to 99.5%. Finally, the photocatalytic activity of APT@MIL was verified by UV-Vis DRS, photoluminescence spectra. The thermodynamic adsorption, kinetic characteristics adsorption, and removal mechanism of APT@MIL are also discussed. In summary, a novel hybrid material APT@MIL was successfully prepared with good adsorption and photocatalytic performance. It is expected to be used in photocatalytic degradation of dye wastewater.


Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 931 ◽  
Author(s):  
Lu Xia ◽  
Zhonghang Huang ◽  
Lei Zhong ◽  
Fengwei Xie ◽  
Chak Tang ◽  
...  

A novel bio-adsorbent was fabricated via grafting an amino-terminated hyperbranched polymer (HBP-NH2) onto bagasse cellulose. The morphology and microstructure of the HBP-NH2-grafted bagasse cellulose (HBP-g-BC) were characterized and its adsorption capacity for Cr(VI) ions in aqueous solutions was investigated. The rough surface structure of HBP-g-BC that is beneficial for improving the adsorption capacity was observed by scanning electron microscopy (SEM). The grafting reaction was confirmed by Fourier-transform infrared (FT-IR) spectroscopy. The adsorbent performance was shown to be better with a lower pH value, a higher adsorbent dosage, or a higher initial Cr(VI) concentration. Moreover, the kinetics study revealed that the adsorption behavior followed a pseudo-second-order model. The isotherm results showed that the adsorption data could be well-fitted by the Langmuir, Freundlich, or Temkin models. Moreover, HBP-g-BC could maintain 74.4% of the initial removal rate even after five cycles of regeneration. Thus, the high potential of HBP-g-BC as a bio-adsorbent for heavy metal removal has been demonstrated.


2012 ◽  
Vol 599 ◽  
pp. 598-601
Author(s):  
Peng Jia ◽  
Ma Hong Yu

The kinetics and thermodynamics of Cu(Ⅱ) biosorption on sludge in the presence of citrate were investigated. Biosorption mechanisms were characterized by biosorption characteristics and modern analysis means such as BET,FT-IR,XRD and SEM. The results show that the system of sludge and complexation of copper reaches equilibrium within 18h and the maximum removal rate of total copper is about 80%. Kinetic studies indicate that pseudo-second order model with correlation coefficients of 0.9959 best fits the biosorption process. The equilibrium of the system follows the Langmuir isotherm model. FT-IR spectral analysis indicates that amides, -OH, COO¯, silicate minerals, phosphate groups and polysaccharides serve as the main active groups. XRD and SEM analysis indicate the crystal shape of sludge changes and metal sediment can be found after biosorption. Adsorption mechanisms contain chelation, precipitation and ion-exchange.


2016 ◽  
Vol 73 (11) ◽  
pp. 2654-2661 ◽  
Author(s):  
Shuxiong Tang ◽  
Yao Chen ◽  
Ruzhen Xie ◽  
Wenju Jiang ◽  
Yanxin Jiang

Operation experiments were conducted to optimize the preparation of activated carbons from corn cob. The Cr(VI) adsorption capacity of the produced activated carbons was also evaluated. The impact of the adsorbent dosage, contact time, initial solution pH and temperature was studied. The results showed that the produced corn cob activated carbon had a good Cr(VI) adsorptive capacity; the theoretical maximum adsorption was 34.48 mg g−1 at 298 K. The Brunauer–Emmett–Teller and iodine adsorption value of the produced activated carbon could be 924.9 m2 g−1 and 1,188 mg g−1, respectively. Under the initial Cr(VI) concentration of 10 mg L−1 and the original solution pH of 5.8, an adsorption equilibrium was reached after 4 h, and Cr(VI) removal rate was from 78.9 to 100% with an adsorbent's dosage increased from 0.5 to 0.7 g L−1. The kinetics and equilibrium data agreed well with the pseudo-second-order kinetics model and the Langmuir isotherm model. The equilibrium adsorption capacity improved with the increment of the temperature.


2015 ◽  
Vol 814 ◽  
pp. 458-463
Author(s):  
Bei Gang Li ◽  
Lei Ding

Fly ash/CeO2 composite (FA/CeO2) was prepared by acid modification and precipitation method using a low-cost waste fly ash (FA) as a raw material and characterized by X-ray diffraction (XRD) and the BET surface analysis. The adsorption of FA and FA/CeO2 for Congo Red (CR) from simulated dye wastewater was studied. The different regeneration methods for the CR-saturated FA/CeO2 were investigated. The results show that the adsorption capacity and removal rate of CR on FA/CeO2 can respectively reach 175.35mg/g and 97.42%, 4.5 times higher than those on FA. The adsorption process of FA/CeO2 for CR at different temperatures (25°C~55°C) can well be described by the pseudo-second-order adsorption model and is mainly controlled by intraparticle diffusion. The adsorption rate decreased slightly with increasing temperature, and the obtained adsorption apparent activation energy is 15.08kJ/mol. This indicates that CR is easily adsorbed on FA/CeO2, and the adsorption of the process is mainly physical adsorption with exothermic nature. The room temperature is favorable to the adsorption and actual operation. NaOH solution of 0.01 mol/L can make CR-saturated FA/CeO2 regenerated three times, and corresponding removal rate for CR can reach 97.82%, 80.21% and 66.04%, respectively. As a new kind of low-cost and high-efficient adsorbent, FA/CeO2 composite has the potential value in the application of wastewater treatment.


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