Effect of iron nitrate modification on elimination of organic matter from landfill leachate by sludge-based activated carbon

2021 ◽  
pp. 0734242X2110099
Author(s):  
Fan Zeng ◽  
Xiaofeng Liao ◽  
Jiawei Lu ◽  
Danping Pan ◽  
Qili Qiu ◽  
...  

Sludge-based activated carbons (SACs) prepared from sewage sludge and corn straw, were modified by ferric nitrate, and the unmodified SAC and modified SAC were used as the adsorbing agent to treat the landfill leachate, the elimination capacity for chemical oxygen demand (COD) and organic matter in leachate were studied. Based on this, the physicochemical properties of SACs and the components changes in leachate were analyzed and characterized by X-ray photoelectron spectroscopy and three-dimensional fluorescence spectroscopy. The results showed that under optimal experimental conditions, the elimination capacities of SAC372 for COD, biological oxygen demand over 5 days, and NH4+–N in the leachate were 81.58%, 54.73%, and 69.08%, respectively; while the adsorption capacities of modified SAC for these three substances were 86.25%, 63.51%, and 79.15%, respectively. The ferric nitrate modification improved the ability of SAC to eliminate COD and organic matter from leachate slightly, and made the adsorption occurred easily. The adsorption process of unmodified SAC was dominated by multi-layer adsorption, while the adsorption process of modified SAC was dominated by monolayer adsorption. The mass fraction of Fe (2p) in modified SAC remarkably increased, from 0.70% to 26.01%, organic functional groups certain phase of Fe oxides with different valence states were generated in SAC, which provided a substrate for iron–carbon micro electrolysis. After adsorbed by unmodified SAC and modified SAC adsorption, the total fluorescence intensity of in the leachate increased by 17.01% and 116.84%, respectively. Both two SACs could decompose the humic acid-like substances into aromatic protein organic compounds, and modified SAC could further decompose the soluble microbial byproduct-like substances.

2018 ◽  
Vol 13 (1) ◽  
pp. 219-228 ◽  
Author(s):  
Kasmi Mariam ◽  
Elleuch Lobna ◽  
Abidi Haifa ◽  
Cherni Yassmine ◽  
Hosni Cyrine ◽  
...  

Abstract In this study the biotreatability of Jebel Chakir landfill leachate (Tunisia) using a mixture of dairy industry reject (bactofugate) and Aloe sp. leaf gel was evaluated. The effect of Aloe gel fermentation using Saccharomyces cerevisiae yeast strain was investigated against some selected bacterial and fungal strains. The inoculation size effect of the treatment mixtures (2, 6, 10 and 12%) in the treatment efficiency was also studied. The obtained results showed that when natural Aloe gel and bactofugate mixtures were used the recorded chemical oxygen demand removal rates exceeded 56% within 48 h of treatment. Whereas, the use of the fermented Aloe gel in the treatment mixtures has promoted the organic matter removal to reach 72%.


2017 ◽  
Vol 76 (10) ◽  
pp. 2655-2663 ◽  
Author(s):  
Xian-Qing Yin ◽  
Bo Jing ◽  
Wen-Juan Chen ◽  
Jian Zhang ◽  
Qian Liu ◽  
...  

Abstract The chemical oxygen demand (COD) removal mechanism and reaction kinetics were mainly studied in the treatment of oilfield oily sewage containing polymer by three-dimensional electrode reactor. The results proved that the residual active oxides O3, H2O2, •OH and active chlorine in the system of electrochemical reaction could be effectively detected, and the COD removal mechanism was co-oxidation of active oxides; Under these experimental conditions: the electrolysis current of 6 A, surface/volume ratio of 6/25(cm2·L−1), the reaction time of 50 min, the CODcr of treated sewage was no more than 50 mg·L−1; the removal reaction of COD conformed to apparent second-order reaction kinetic model, the correlation coefficient R2 was 0.9728, and the apparent reaction rate constant was k = 3.58 × 10−4 (L·min−1·mg−1·m−2). To reach the goal, the CODcr was no more than 50 mg·L−1 in treated sewage, and the theory minimum processing time was 45.73 min. The verification of experimental results was consistent with kinetic equations.


2013 ◽  
Vol 21 (1) ◽  
pp. 32-44 ◽  
Author(s):  
V. N. Strocov ◽  
X. Wang ◽  
M. Shi ◽  
M. Kobayashi ◽  
J. Krempasky ◽  
...  

Soft-X-ray angle-resolved photoelectron spectroscopy (ARPES) with photon energies around 1 keV combines the momentum space resolution with increasing probing depth. The concepts and technical realisation of the new soft-X-ray ARPES endstation at the ADRESS beamline of SLS are described. The experimental geometry of the endstation is characterized by grazing X-ray incidence on the sample to increase the photoyield and vertical orientation of the measurement plane. The vacuum chambers adopt a radial layout allowing most efficient sample transfer. High accuracy of the angular resolution is ensured by alignment strategies focused on precise matching of the X-ray beam and optical axis of the analyzer. The high photon flux of up to 1013 photons s−1(0.01% bandwidth)−1delivered by the beamline combined with the optimized experimental geometry break through the dramatic loss of the valence band photoexcitation cross section at soft-X-ray energies. ARPES images with energy resolution up to a few tens of meV are typically acquired on the time scale of minutes. A few application examples illustrate the power of our advanced soft-X-ray ARPES instrumentation to explore the electronic structure of bulk crystals with resolution in three-dimensional momentum, access buried heterostructures and study elemental composition of the valence states using resonant excitation.


2014 ◽  
Vol 70 (12) ◽  
pp. 1941-1947 ◽  
Author(s):  
R. Campos ◽  
F. M. Ferraz ◽  
E. M. Vieira ◽  
J. Povinelli

This study investigated the co-treatment of landfill leachate/domestic wastewater in bench-scale activated sludge (AS) reactors to determine whether the slowly biodegradable organic matter (SBOM) was removed rather than diluted. The AS reactors were loaded with mixtures of raw leachate and leachate that was pretreated by air stripping. The tested volumetric ratios were 0%, 0.2%, 2% and 5%. For all of the tested conditions, the reactors performed better when pretreated leachate was used rather than raw leachate, and the best volumetric ratio was 2%. The following removals were obtained: 97% for the biochemical oxygen demand (BOD5,20), 79% for total suspended solids, 77% for dissolved organic carbon and 84% for soluble chemical oxygen demand. Most of the pretreated leachate SBOM (65%) was removed rather than diluted or adsorbed into the sludge, as confirmed by Fourier transform infrared (FTIR) spectroscopy analyses.


2014 ◽  
Vol 17 (4) ◽  
pp. 243-249
Author(s):  
Peng Li ◽  
Yuemin Zhao ◽  
Lizhang Wang ◽  
Binbin Ding ◽  
Yunlong Hu

An efficient organic-matter (OM) degradation strategy using synthetic electrocatalysis particles as fixed filler in a threedimension electrode reactor was developed. In our work, SnO2-granular active carbon (SnO2-GAC) was prepared by integrating GAC with nano-SnO2 via the sol-gel method, using SnCl4 as starting material and gelatin as a stabilizer. The phase composition and micromorphology of the particles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and scanning/transmission electron microscopy techniques. The results showed the incorporation of SnO2 crystallized in a tetragonal lattice with an average crystallite size of 10.6 nm, which was easily accessible on the GAC surface and mesopores. Electrochemical properties were tested with cyclic voltammetry and electrochemical impedance spectroscopy methods that disclosed an improved response current with a simultaneous increase in anodic area, while the charge-transfer and electrolyte resistance obviously decreased, in contrast to the virgin GAC filler in the three-dimension electrode system. Although the energy consumption of SnO2-GAC (11.71 kWh·kg−1 COD) presented slight superiority than that of GAC (13.62 kWh·kg−1 COD) at the same chemical oxygen demand (COD) conversion of 98 % when a current density of 20 A·m−2 was employed for phenolic wastewater treatment, the required degradation time of the former (47.22 h) is greatly decreased compared with that of the latter (54.24 h). These results obviously confirm the superiority of the prepared SnO2-GAC in electro-oxidation of organic matters.


2019 ◽  
Vol 24 (4) ◽  
pp. 833-842 ◽  
Author(s):  
Rodrigo Poblete Chávez ◽  
Ernesto Cortes Cortés Pizarro ◽  
Yolanda Luna Galiano

ABSTRACT A set of experiments were carried out in order to establish and evaluate the potential of activated carbon, produced from coffee waste in adsorption process, in the depuration of landfill leachate. Different reagents were studied in the activation of carbon: HCl, HCl + H2O2, H3PO4, H3PO4 + H2O2, all with an impregnation rate of 1:1. The activated carbon that showed the best global results was activated with H3PO4, obtaining a 51.0, 32.8, 66.0, 81.0 and 97.1% elimination of chemical oxygen demand, ammonia, total chlorine, bromine and copper, respectively. This activated carbon has a total pore area of 4.85 m2/g and a median pore diameter of 65.32 micrometers. When different loads of this carbon were placed in a stirrer system in contact with landfill leachate, with the aim of evaluating the effect of the adsorption load and contact time, the concentration of ammonia decreased from the beginning of the adsorption process to the end of it, and the removal of ammonia increased with the increase in the adsorbent load. However, the trend of the amount adsorbed per unit mass decreased with increased dosage. The model Freundlich equilibrium isotherm fits experimental data adequately, giving R2 values of 0.95, 1/n of 0.5183, and a K value of 7.08*10-5 L/g, being favourable for adsorption process.


2020 ◽  
Vol 12 (7) ◽  
pp. 953-960
Author(s):  
Bo Peng ◽  
Di Qiu ◽  
Xiaogang Wu

To efficiently treat landfill leachate, we prepared a new integrated submerged membrane bioreactor (SMBR) and oxidation technology. Our results, under organic loading rates of 2.0–2.3 kg COD/(m3 ·d), showed that through SMBR we can acquire removal efficiencies of 91.2% and 87.3% for ammonia and chemical oxygen demand (COD), respectively. A Ti/RuO2–IrO2 anode and stainless-steel cathode combination was engaged to carry out electrochemical oxidation of SMBR permeate. Ammonia and COD were removed after 3 h electrochemical oxidation (at 40 mA/cm2 current density), and achieved 93.5% and 66.9% removal efficiency with activated carbon particle electrode introduced in the three-dimensional electrodes, respectively. The higher removal efficiency for ammonia nitrogen than COD can be rendered by excited chloride ions, as they affect the competition between organic matter and ammonia nitrogen. Thus, SMBR combined with electrochemical oxidation possesses good prospects to be applied for efficient reduction of ammonia and COD in landfill leachates.


2012 ◽  
Vol 531 ◽  
pp. 407-410
Author(s):  
Xiao Yan Tan ◽  
Guo Lan Li ◽  
Song Li

Coal-based Activated carbon was modified by thermal and nitric acid treatment to adsorb phenol from aqueous solution. Boehm titration, point of zero charge ( pHPZC ) and X-photoelectron spectroscopy (XPS) were used to characterize activated carbons. Acid treatment leads to the increase of the content of surface oxygen, whereas thermal treatment causes the decrease of the content of surface oxygen.The surface characteristics of activated carbons have significant effect on phenol adsorption. The adsorption isotherms of phenol adsorption are described by Langmuir isotherm. The kinetic studies indicate that the adsorption process is fitted well by the pseudo-second- order kinetics.


Author(s):  
Roberto D’Amato ◽  
Anna Donnadio ◽  
Mariolino Carta ◽  
Claudio Sangregorio ◽  
Riccardo Vivani ◽  
...  

Reaction of cerium ammonium nitrate and tetrafluoroterephthalic acid in water afforded two new metal-organic frameworks with UiO-66 [F4_UiO-66(Ce)] and MIL-140 [F4_MIL-140A(Ce)] topologies. The two compounds can be obtained in the same experimental conditions, just by varying the amount of acetic acid used as crystallization modulator in the synthesis. Both F4_UiO-66(Ce) and F4_MIL-140A(Ce) feature pores with size < 8 Å, which classifies them as ultramicroporous. Combination of X-ray photoelectron spectroscopy and magnetic susceptibility measurements revealed that both compounds contain a small amount of Ce(III), which is preferentially accumulated near the surface of the crystallites. The CO<sub>2</sub> sorption properties of F4_UiO-66(Ce) and F4_MIL-140A(Ce) were investigated, finding that they perform better than their Zr-based analogues. F4_MIL-140A(Ce) displays an unusual S-shaped isotherm with steep uptake increase at pressure < 0.2 bar at 298 K. This makes F4_MIL-140A(Ce) exceptionally selective for CO<sub>2</sub> over N<sub>2</sub>: the calculated selectivity, according to the ideal adsorbed solution theory for a 0.15:0.85 mixture at 1 bar and 293 K, is higher than 1900, amongst the highest ever reported for metal-organic frameworks. The calculated isosteric heat of CO<sub>2 </sub>adsorption is in the range of 38-40 kJ mol<sup>-1</sup>, indicating a strong physisorptive character.


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