Thermal Behavior of Cd During Sludge Incineration: Experiments and Thermodynamic Equilibrium Model.

Experiments and thermodynamic equilibrium calculations were performed to investigate the behavior of Cd during sewage sludge incineration. The chemical equilibrium calculations indicated that chlorine significantly increased the volatilization of Cd in the form of CdCl2. In addition, SiO2-containing materials can function as sorbents for stabilizing Cd. The effect of PVC added to the sludge on the migration of Cd in the sludge was greater than that of NaCl. As the temperature increased, both organic and inorganic chlorides reduced the Cd distribution in the bottom ash. The chloride concentration, and the incineration time exhibited insignificant changes in Cd emission. With the addition of either NaCl or PVC into the sludge, the phases of Cd present in the bottom slag were primarily present in the form of silica-alumina oxides or multi-metal oxide, which could inhabit the Cd volatilization.

Thermodynamic Equilibrium Calculations on Cd Transformation during Sewage Sludge Incineration.

Thermodynamic equilibrium calculations were performed to reveal the distribution of cadmium during the sewage sludge incineration process. During sludge incineration in the presence of major minerals, such as SiO2, Al2O3 and CaO, the strongest effect was exerted by SiO2 on the Cd transformation compared with the effect of others. The stable solid product of CdSiO3 was formed easily with the reaction between Cd and SiO2, which can restrain the emissions of gaseous Cd pollutants. CdCl2 was formed more easily in the presence of chloride during incineration, thus, the volatilization of Cd was advanced by increasing chlorine content. At low temperatures, the volatilization of Cd was restrained due to the formation of the refractory solid metal sulfate. At high temperatures, the speciation of Cd was not affected by the presence of sulfur, but sulfur could affect the formation temperature of gaseous metals.

An experimental and thermodynamic equilibrium investigation of the Pb, Zn, Cr, Cu, Mn and Ni partitioning during sewage sludge incineration.

The effects of different chlorides and operational conditions on the distribution and speciation of six heavy metals (Pb, Zn, Cr, Cu, Mn and Ni) during sludge incineration were investigated using a simulated laboratory tubular-furnace reactor. A thermodynamic equilibrium investigation using the FactSage software was performed to compare the experimental results. The results indicate that the volatility of the target metals was enhanced as the chlorine concentration increased. Inorganic-Cl influenced the volatilization of heavy metals in the order of Pb>Zn>Cr>Cu>Mn>Ni. However, the effects of organic-Cl on the volatility of Mn, Pb and Cu were greater than the effects on Zn, Cr and Ni. With increasing combustion temperature, the presence of organic-Cl (PVC) and inorganic-Cl (NaCl) improved the transfer of Pb and Zn from bottom ash to fly ash or fuse gas. However, the presence of chloride had no obvious influence on Mn, Cu and Ni. Increased retention time could increase the volatilization rate of heavy metals; however, this effect was insignificant. During the incineration process, Pb readily formed PbSiO4 and remained in the bottom ash. Different Pb compounds, primarily the volatile PbCl2, were found in the gas phase after the addition of NaCl; the dominant Pb compounds in the gas phase after the addition of PVC were PbCl2, Pb(ClO4)2 and PbCl2O4.

Simultaneous removal of Cr(â ¥) and tetracycline from wastewater by dielectric barrier discharge plasma coupled with TiO2/rGO/Cu2O composites: Performance and mechanism.

In this study, dielectric barrier discharge (DBD) plasma combined with titanium dioxide/reduced graphene oxide/copper oxide (TiO2/rGO/Cu2O) composites for simultaneous removal of hexavalent chromium (Cr(Ⅵ)) and tetracycline (TC) from wastewater were explored systematically. The TiO2/rGO/Cu2O composites were successfully prepared to improve the specific surface area and charge carrier separation rate. When Cr(Ⅵ) and TC coexist, the two pollutants have better removal efficiency without changing the initial pH. Moreover, the removal efficiency of Cr(Ⅵ) and TC could be further improved in the DBD-TiO2/rGO/Cu2O system, indicating that the TiO2/rGO/Cu2O composites also exhibited good synergistic effects with the DBD plasma. The mechanism exploration showed that the TiO2/rGO/Cu2O composite catalyst could be activated in DBD system to produce various active species by photocatalytic reaction, among which photo-generated electrons and •O2- could significantly enhance Cr(Ⅵ) reduction, while photo-generated holes and •OH could improve TC degradation. More importantly, the intermediate products obtained from TC degradation can be oxidized to •CO2- by photo-generated holes, which can also facilitate the reduction of Cr(Ⅵ). This study shows that DBD combined with TiO2/rGO/Cu2O composites are capable of simultaneous Cr(Ⅵ) reduction and TC degradation, which would provide novel ideas for practical wastewater remediation.

Optimizing co-combustion synergy of soil remediation biomass and pulverized coal toward energetic and gas-to-ash pollution controls.

The co-combustion synergy of post-phytoremediation biomass may be optimized to cultivate a variety of benefits from reducing dependence on fossil fuels to stabilizing heavy metals in a small quantity of ash. This study characterized the thermo-kinetic parameters, gas-to-ash products, and energetically and environmentally optimal conditions for the co-combustions of aboveground (PG-A) and belowground (PG-B) biomass of Pfaffia glomerata (PG) with pulverized coal (PC). The mono-combustions of PG-A and PG-B involved the decompositions of cellulose and hemicellulose in the range of 162-400 °C and of lignin in the range of 400-600 °C. PG improved the combustion performance of PC, with the blends of 30 % PG-A and 70 % (PAC37) and 10 % PG-B and 90 % PC (PBC19) exhibiting the strongest synergy. Both PG-A and PG-B interacted with PC in the range of 160-440 °C, while PC positively affected PG in the range of 440-600 °C. PC decreased the apparent activation energy (Eα) of PG, with PBC19 having the lowest Eα value (107.85 kJ/mol). The reaction order models (Fn) best elucidated the co-combustion mechanisms of the main stages. Adding >50 % PC reduced the alkali metal content of PG, prevented the slagging and fouling depositions, and mitigated the Cd and Zn leaching toxicity. The functional groups, volatiles, and N- and S-containing gases fell with PAC37 and PBC19, while CO2 emission rose. Energetically and environmentally multiple objectives for the operational conditions were optimized via artificial neural networks. Our study presents controls over the co-circularity and co-combustion of the soil remediation plant and coal.

Actionable insights into hazard mitigation of typical 3D printing waste via pyrolysis.

3D printing waste (3DPW) contains hazardous substances, such as photosensitizers and pigments, and may cause environmental pollution when improperly disposed of. Pyrolysis treatment can reduce hazards and turn waste into useful resources. This study coupled thermogravimetric (TG), TG-Fourier transform infrared spectroscopy-gas chromatography/mass spectrometry, and rapid pyrolysis gas chromatography/mass spectrometry analysis to evaluate the pyrolytic reaction mechanisms, products, and possible decomposition pathways of the three typical 3DPW of photosensitive resin waste (PRW), polyamide waste (PAW), and polycaprolactone waste (PCLW). The main degradation stages of the typical 3DPW occurred at 320-580 °C. The most appropriate reaction mechanisms of PRW, PAW and PCLW were D1, A1.2 and A1.5, respectively. The main pyrolysis processes were the decomposition of the complex organic polymers of PRW, the breaking of the NH-CH2 bond and dehydration of -CO-NH- of PAW, and the breaking and reorganization of the molecular chains of PCLW, mainly resulting in toluene (C7H8), undecylenitrile (C11H21N), tetrahydrofuran (C4H8O), respectively. Unlike the slow pyrolysis, the rapid pyrolysis produced volatiles consisting mainly of phenol, 4,4'-(1-methylethylidene)bis- (C15H16O2) for PRW; 1,10-dicyanodecane (C12H20N2) for PAW; and ɛ-caprolactone (C6H10O2) for PCLW. These pyrolysis products hold great potential for applications. The findings of the study offer actionable insights into the hazard reduction and resource recovery of 3D printing waste.

Dynamic pyrolytic reaction mechanisms, pathways, and products of medical masks and infusion tubes.

Given the COVID-19 epidemic, the quantity of hazardous medical wastes has risen unprecedentedly. This study characterized and verified the pyrolysis mechanisms and volatiles products of medical mask belts (MB), mask faces (MF), and infusion tubes (IT) via thermogravimetric, infrared spectroscopy, thermogravimetric-Fourier transform infrared spectroscopy, and pyrolysis-gas chromatography/mass spectrometry analyses. Iso-conversional methods were employed to estimate activation energy, while the best-fit artificial neural network was adopted for the multi-objective optimization. MB and MF started their thermal weight losses at 375.8 °C and 414.7 °C, respectively, while IT started to degrade at 227.3 °C. The average activation energies were estimated at 171.77, 232.79, 105.14, and 205.76 kJ/mol for MB, MF, and the first and second IT stages, respectively. Nucleation growth for MF and MB and geometrical contraction for IT best described the pyrolysis behaviors. Their main gaseous products were classified, with a further proposal of their initial cracking mechanisms and secondary reaction pathways.

Efficiency, by-product valorization, and pollution control of co-pyrolysis of textile dyeing sludge and waste solid adsorbents: Their atmosphere, temperature, and blend ratio dependencies.

This study aimed to quantify the co-pyrolytic synergistic effects of textile dyeing sludge (TDS) and waste biochar (WBC) for an optimal utilization of secondary resources and to mitigate environmental pollution and waste volume. TDS and WBC had a strong synergistic effect between 800 and 900 °C in the CO2-assisted atmosphere. With the increased TDS fraction, NH3 emission fell significantly regardless of the atmosphere type. The CO2 atmosphere changed S in TDS char and released SO2 in the range of 800-1000 °C. With the temperature rise, an unstable N structure turned into a more stable heterocyclic N structure in the CO2 and N2 atmospheres. Regardless of the atmosphere type and temperature, the C-containing functional groups in co-pyrolytic biochar existed mainly as C-C/C-H. In the CO2 atmosphere, inorganic S, aliphatic S, and thiophene S in the co-pyrolytic biochar disappeared and became more stable sulfones. The co-pyrolysis inhibited the formation of S-containing compounds. The retention ability of the co-pyrolytic biochar peaked for most of the heavy metals in the N2 atmosphere but was better for Pb and Zn in the CO2 than N2 atmosphere. Simultaneous optimization showed the co-pyrolysis of 10% TDS and 90% WBC at above 950 °C in the N2-CO2 or CO2 atmosphere as the optimal operational settings combined.

Co-combustion, life-cycle circularity, and artificial intelligence-based multi-objective optimization of two plastics and textile dyeing sludge.

Given the globally abundant availability of waste plastics and the negative environmental impacts of textile dyeing sludge (TDS), their co-combustion can effectively enhance the circular economies, energy recovery, and environmental pollution control. The (co-)combustion performances, gas emissions, and ashes of TDS and two plastics of polypropylene (PP) and polyethylene (PE) were quantified and characterized. The increased blend ratio of PP and PE improved the ignition, burnout, and comprehensive combustion indices. The two plastics interacted with TDS significantly in the range of 200-600 â„ƒ. TDS pre-ignited the combustion of the plastics which in turn promoted the combustion of TDS. The co-combustions released more CO2 but less CH4, C-H, and CO as CO2 was less persistent than the others in the atmosphere. The Ca-based minerals in the plastics enhanced S-fixation and reduced SO2 emission. The activation energy of the co-combustion fell from 126.78 to 111.85 kJ/mol and 133.71-79.91 kJ/mol when the PE and PP additions rose from 10% to 50%, respectively. The co-combustion reaction mechanism was best described by the model of f(α) = (1-α)n. The reaction order was reduced with the additions of the plastics. The co-combustion operation interactions were optimized via an artificial neural network so as to jointly meet the multiple objectives of maximum energy production and minimum emissions.

Coupled mechanisms of reaction kinetics, gas emissions, and ash mineral transformations during combustion of AlCl3-conditioned textile dyeing sludge.

Though commonly used in the dewatering of textile dyeing sludge (TDS) before its incineration, chemical conditioning has yet to be evaluated in terms of its impact on the reaction mechanisms, emissions, and ash minerals. This study combined experiments and equilibrium simulations to disentangle the interaction mechanism among the combustion behaviors, gas emissions, ash minerals of TDS conditioned with(out) three blend ratios of the AlCl3 conditioner. The use of the AlCl3 conditioner slightly improved the performance of the combustion stage of volatiles and chars. No significant effect of AlCl3 conditioner was detected on the kinetic mechanism of its main combustion stage best elucidated by the nth-order and diffusion models. SO2 was the main evolved gas whose reduction between 600 and 800 °C was attributed to its increased retention rate by CaO from the decomposition of CaCO3. Aluminum compounds acted as a stimulator in SO2 emission between 800 and 1000 °C since the formation of calcium aluminosilicates. At above 1060 °C, CaSO4 decomposed rapidly, thus almost completely releasing inorganic S. This study supplies new insights into pollution `controls on the combustion of TDS conditioned with Al salt coagulant.

Ash-to-emission pollution controls on co-combustion of textile dyeing sludge and waste tea.

Given the globally increased waste stream of textile dyeing sludge (TDS), its co-combustion with agricultural residues appears as an environmentally and economically viable solution in a circular economy. This study aimed to quantify the migrations and chemical speciations of heavy metals in the bottom ashes and gas emissions of the co-combustion of TDS and waste tea (WT). The addition of WT increased the fixation rate of As from 66.70 to 83.33% and promoted the chemical speciation of As and Cd from the acid extractable state to the residue one. With the temperature rise to 1000 °C, the fixation rates of As, Cd, and Pb in the bottom ashes fell to 27.73, 8.38, and 15.40%, respectively. The chemical speciation perniciousness of Zn, Cu, Ni, Mn, Cr, Cd, and Pb declined with the increased temperature. The ash composition changed with the new appearances of NaAlSi3O8, CaFe2O4, NaFe(SO4)2, and MgCrO4 at 1000 °C. The addition of WT increased CO2 and NOx but decreased SO2 emissions in the range of 680-1000 °C. ANN-based joint optimization indicated that the co-combustion emitted SO2 slightly less than did the TDS combustion. These results contribute to a better understanding of ash-to-emission pollution control for the co-combustion of TDS and WT.

Optimizing environmental pollution controls in response to textile dyeing sludge, incineration temperature, CaO conditioner, and ash minerals.

The dynamics of heavy metal speciation and flue gas emissions during the incineration of textile dyeing sludge (TDS) were quantified as a function of four addition levels of CaO, incineration temperature, and ash minerals using thermogravimetric analysis and experimental tube furnace. The TDS incineration was most improved with the addition of 10% CaO. The increased fractions of CaO coupled with the ash minerals changed the retention behaviors of eight heavy metals. The CaO addition increased the Cu, Zn, As, and Pb retentions, did not significantly change Cr, Mn, and Cd, but decreased the Ni retention. The CaO addition enhanced the speciation stability of Cu and transferred the Cr, Cd, and As speciations to the mobile fractions. The increased temperature weakened the Zn and Pb retentions and the speciation stabilities of As and Pb and turned the Cr, Mn, Ni, Cu, Zn, and Cd speciations into the stable fractions. The CaO addition inhibited HCN, NO, NO2, COS, SO2, CS2, and SO3 emissions from the TDS incineration. Neural network-based multi-response optimization was implemented to determine the optimal operational temperature for the TDS incineration and the reduction of the 12 gas emissions. The range of 640-755 °C with(out) 5% CaO appeared to be most beneficial in terms of both environmental quality and economic efficiency.

Do FeCl3 and FeCl3/CaO conditioners change pyrolysis and incineration performances, emissions, and elemental fates of textile dyeing sludge?

The pyrolysis and incineration performances of sulfur-rich textile dyeing sludge (TDSS) were determined in response to the additions of FeCl3 or FeCl3 + CaO. The emissions of eight air pollutants from the incineration and pyrolysis were systematically identified. The 3-to-8% FeCl3 additions increased the comprehensive combustibility index by 2.14 and 1.62 times, respectively, as opposed to the 5-to-10% FeCl3 + 8-to-15% CaO additions. The CaO addition inhibited the TDSS incineration, while the FeCl3 addition increased HCl emission. NOx, SO2, and H2S emissions decreased initially and increased between 600 and 950 °C. SO2 and NOx emissions rose with FeCl3 but FeCl3 + CaO. FeCl3 catalyzed NOx, while CaO retained SO2. The main pyrolysis gas/liquid products were alkane, alkenes, nitrile, heterocyclic compounds, benzene, and its derivatives. Benzene and its derivatives accounted for 55.33% of the control group and 42.25-57.23% of the treatment groups. The FeCl3 and FeCl3 + CaO additions did not significantly influence the pyrolysis products. The measured versus thermodynamically simulated SOx and HCl emissions were consistent. Neural network-based simultaneous optimizations of the non-linear dynamics of eight kinds of gases pointed to 50% and 14.4% reductions in the emissions and the pyrolytic temperature, respectively, with the 3% FeCl3, relative to the control.

Comparative (co-)pyrolytic performances and by-products of textile dyeing sludge and cattle manure: Deeper insights from Py-GC/MS, TG-FTIR, 2D-COS and PCA analyses.

Not only does pyrolysis recover energy and value-added by-products but also reduces waste stream volume. The low volatiles and high ash contents of textile dyeing sludge (TDS) limit its mono-pyrolysis performance. This study aimed to conduct an in-depth analysis of its co-pyrolytic performance with cattle manure (CM). The co-pyrolysis enhanced the volatiles emission from the early devolatilization stage whose reaction mechanism shifted from a diffusion model to a reaction-order model. The further cracking of macromolecular materials was mainly elucidated by the reaction-order model. The temperature dependency of the co-pyrolytic gases was of the following order: aliphatic hydrocarbons > CO2 > alcohols, phenols, ethers, aldehydes, ketones, and carboxylic acids. The main co-pyrolytic volatile products were coumaran and 4-vinylguaiacol. The relative content of guaiacol-type components could be enhanced by co-pyrolysis and lowering the operational temperature to 450 °C. The interaction of co-pyrolysis enriched the char aromaticity. Our findings provide practical insights into the control and application opportunities and limitations on the high value-added energy and products from the co-pyrolysis of TDS and CM.

Dynamic pyrolysis behaviors, products, and mechanisms of waste rubber and polyurethane bicycle tires.

Given their non-biodegradable, space-consuming, and environmentally more benign nature, waste bicycle tires may be pyrolyzed for cleaner energies relative to the waste truck, car, and motorcycle tires. This study combined thermogravimetry (TG), TG-Fourier transform infrared spectroscopy (TG-FTIR), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) analyses to dynamically characterize the pyrolysis behavior, gaseous products, and reaction mechanisms of both waste rubber (RT) and polyurethane tires (PUT) of bicycles. The main devolatilization process included the decompositions of the natural, styrene-butadiene, and butadiene rubbers for RT and of urethane groups in the hard segments, polyols in the soft segments, and regenerated isocyanates for PUT. The main TG-FTIR-detected functional groups included C-H, C=C, C=O, and C-O for both waste tires, and also, N-H and C-O-C for the PUT pyrolysis. The main Py-GC/MS-detected pyrolysis products in the decreasing order were isoprene and D-limonene for RT and 4, 4'-diaminodiphenylmethane and 2-hexene for PUT. The kinetic, thermodynamic, and comprehensive pyrolysis index data verified the easier decomposition of PUT than RT. The pyrolysis mechanism models for three sub-stages of the main devolatilization process were best described by two-dimensional diffusion and two second-order models for RT, and the three consecutive reaction-order (three-halves order, first-order, and second-order) models for PUT.

Emission-to-ash detoxification mechanisms of co-combustion of spent pot lining and pulverized coal.

In response to the global initiative for greenhouse gas emission reduction, the co-combustion of coal and spent pot lining (SPL) may cost-effectively minimize waste streams and environmental risks. This study aimed to quantify the emission-to-ash detoxification mechanisms of the co-combustion of SPL and pulverized coal (PC) and their kinetics, gas emission, fluorine-leaching toxicity, mineral phases, and migrations. The main reaction covered the ranges of 335-540 °C and 540-870 °C while the interactions occurred at 360-780 °C. The apparent activation energy minimized (66.99 kJ/mol) with 90% PC addition. The rising PC fraction weakened the peak intensity of NaF and strengthened that of Ca2F, NaAlSiO4, and NaAlSi2O6. The addition of PC enhanced the combustion efficiency of SPL and raised the melting temperature by capturing Na. PC exhibited a positive effect on solidifying water-soluble fluorine and stabilizing alkali and alkaline earth metals. The leaching fluorine concentrations of the co-combustion ashes were lower than did SPL mono-combustion. The main gases emitted were HF, NH3, NOx, CO, and CO2. HF was largely released at above 800 °C. Multivariate Gaussian process model-based optimization of the operational conditions also verified the gas emissions results. Our study synchronizes the utilization and detoxification of SPL though co-combustion and provides insights into an eco-friendlier life-cycle control on the waste-to-energy conversion.

Thermal behaviors of fluorine during (co-)incinerations of spent potlining and red mud: Transformation, retention, leaching and thermodynamic modeling analyses.

Spent potlining (SPL) as a hazardous solid waste has a high content of inorganic fluorine. This study aimed at characterizing its transformation, retention and leaching behaviors with(out) the addition of red mud (RM) during the SPL incineration. The RM addition positively affected its retention and leaching rates. Its Ca-containing compounds caused Na3AlF6 and NaF to turn into more CaF2. 30% RM converted water-soluble NaF into more stable CaF2 than did SPL at 850 °C, thus reducing the leaching rate by 45.15%. 30% RM captured HF through its Ca content and enhanced its retention rate by 66.96%. 66.01% of the total fluorine was stably retained in the bottom ash, and thus, significantly reduced the toxicity of the SPL incineration products. SiO2 and Al2O3 exerted a thermally positive effect on NaF turning into CaF2. The fluoride retention of the bottom ash was mainly dominated by CaF2 and NaF with(out) RM. Smaller, coarser and more loose structures of the co-incinerated solid particles pointed to a synergistic interaction between SPL and RM.

Characterizing and optimizing (co-)pyrolysis as a function of different feedstocks, atmospheres, blend ratios, and heating rates.

(Co-)pyrolysis behaviors were quantified using TG and Py-GC/MS analyses as a function of the two fuels of sewage sludge (SS) and water hyacinth (WH), five atmospheres, six blend ratios, and three heating rates. Co-pyrolysis performance, gaseous characterizations and optimization analyses were conducted. Relative to N2 atmosphere, co-pyrolysis was inhibited at low temperatures in CO2 atmosphere, while the CO2 atmosphere at high temperatures promoted the vaporization of coke. The main (co-)pyrolysis products of SS and WH were benzene and its derivatives, as well as alkenes and heterocyclic compounds. Average apparent activation energy decreased gradually with the increased atmospheric CO2 concentration and was highest (377.5 kJ/mol) in N2 atmosphere and lowest (184.7 kJ/mol) in CO2 atmosphere. Significant interaction effects on the mean responses of mass loss, derivative TG, and differential scanning calorimetry were found for fuel type by heating rate and atmosphere type by heating rate.

Kinetics, thermodynamics, gas evolution and empirical optimization of (co-)combustion performances of spent mushroom substrate and textile dyeing sludge.

Spent mushroom substrate (SMS) and textile dyeing sludge (TDS) were (co-)combusted in changing heating rates, blend ratios and temperature. The increased blend ratio improved the ignition, burnout and comprehensive combustion indices. A comparison of theoretical and experimental thermogravimetric curves pointed to significant interactions between 350 and 600 °C. High content of Fe2O3 in TDS ash may act as catalysis at a high temperature. Ignition activation energy was lower for TDS than SMS due to its low thermal stability. 40% SMS appeared to be the optimal blend ratio that significantly decreased the activation energy, as was verified by the response surface methodology. D3 model best described the (co-)combustions. SMS led to more NO and NO2 emissions at about 300 °C and less HCN emission than did TDS. The addition of 40% SMS to TDS lowered SO2 emission. The co-combustion of TDS and SMS appeared to enhance energy generation and emission reduction.

Decomposition of Nickel(⠡)-Ethylenediaminetetraacetic acid by Fenton-Like reaction over oxygen vacancies-based Cu-Doped Fe3O4@γ-Al2O3 catalyst: A synergy of oxidation and adsorption.

Nickel (Ⅱ)-ethylenediaminetetraacetic acid (Ni-EDTA) complexes are widely present in electroplating effluents. Owing to its chemical stability, Ni-EDTA is hardly removed in traditional Fenton/Fenton-like processes with conventional iron (Fe)-based catalyst. In this study, oxygen vacancies were introduced into our highly efficient and novel Fe3O4@γ-Al2O3 catalysts using Cu doping for Ni-EDTA decomposition in Fenton-like system. Without noble-metal cocatalyst, the introduction of oxygen vacancies in Cu-doped Fe3O4@γ-Al2O3 catalysts exhibit excellent Fenton-like activity even in neutral or alkaline conditions. Experimental results revealed that, without the aid of extra energy, Ni-EDTA complexes could be effectively decomposed over oxygen vacancies-based catalyst. Electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), oxygen temperature-programmed desorption (O2-TPD), and hydrogen temperature-programmed reduction (H2-TPR) were used to get a deep insight into the decomposition mechanism. Additionally, by employing the Al-containing support, stable layered double-hydroxide phases of NiAl could be formed, indicating that a synergy of oxidation and adsorption could simultaneously take place, which led to the recovery of released Ni2+ ions and also reduction in secondary pollution. To investigate the decomposition process of Ni-EDTA over oxygen vacancies-based catalyst, liquid chromatography-quadrupole/electrostatic field orbitrap high resolution mass spectrometry (LC-MS/MS) was employed to identify the generated intermediates, and thus, a plausible decomposition pathway was successfully conceived.