Closed-loop hydrometallurgical treatment of end-of-life lithium ion batteries: Towards zero-waste process and metal recycling in advanced batteries

This work presents an enhanced hydrometallurgical process for recycling lithium ion batteries. First, endof-life batteries were processed in a physical pre-treatment plant to obtain a representative electrode material. The resulting leachate was purified forth by iron-precipitation, liquid–liquid extractions, and an innovative Li–Na separation, in order to obtain valuable products. These products include high-grade graphite, cobalt oxide(Co3O4, purity 83%), cobalt oxalate(CoC2O4, purity 96%), nickel oxide(Ni O, purity89%), and lithium carbonate(Li2CO3, purity 99.8%). The recovery rate was quantitative for graphite, between 80% and 85% for cobalt depending on the nature of the recovery method, 90% for nickel, and 72%for lithium. Secondary streams were also valorized to obtain sodium sulfate(Na2SO4, purity 96%), and MnCoFe2O4 magnetic nano-sorbents according to the zero-waste concept. In order to close the loop, recycled Co3O4 and NiO were used as conversion-type anode materials for advanced lithium ion batteries showing promising performances.

Peracetic acid(PAA)-based pretreatment effectively improves medium-chain fatty acids(MCFAs)production from sewage sludge

Peracetic acid(PAA),known for its environmentally friendly properties as a oxidant and bactericide,is gaining prominence in decontamination and disinfection applications.The primary product of PAA oxidation is acetate that can serve as an electron acceptor(EA)for the biosynthesis of medium-chain fatty acids(MCFAs)via chain elongation(CE)reactions.Hence,PAA-based pretreatment is supposed to be beneficial for MCFAs production from anaerobic sludge fermentation,as it could enhance organic matter availability,suppress competing microorganisms and furnish EA by providing acetate.However,such a hypothesis has rarely been proved.Here we reveal that PAA-based pretreatment leads to significant exfoliation of extracellular polymeric substances(EPS)from sludge flocs and disruption of proteinic secondary structures,through inducing highly active free radicals and singlet oxygen.The production of MCFAs increases substantially to 11,265.6 mg COD L^(-1),while the undesired byproducts,specifically long-chain alcohols(LCAs),decrease to 723.5 mg COD L^(-1).Microbial activity tests further demonstrate that PAA pretreatment stimulates the CE process,attributed to the up-regulation of functional genes involved in fatty acid biosynthesis pathway.These comprehensive findings provide insights into the effectiveness and mechanisms behind enhanced MCFAs production through PAA-based technology,advancing our understanding of sustainable resource recovery from sewage sludge.

Synergistic effects of peroxydisulfate on UV/O_(3) process for tetracycline degradation:Mechanism and pathways

Tetracycline(TC)as a typical emerging pollutant is becoming a serious threat to the environment and human health.A combined advanced oxidation technology of UV/Ozone(O_(3))/peroxydisulfate(PDS)process was developed to explore an efficient and economic treatment process of TC in wastewater.Furthermore,the reactive sites and transformation pathways of TC were explored and the toxicity of the intermediates was quantified with a quantitative structure-activity relationship(QSAR)assessment.The degradation performance of TC was substantially enhanced in UV/O_(3)/PDS process with a kobsof 0.0949 min-1,which was 2.3 times higher than UV/O_(3)and 3.2 times than sole UV.The results demonstrated that there was a superior synergistic effect of PDS on UV/O_(3)processes for the degradation of TC.Electron paramagnetic resonance(EPR)analysis and quenching experiments show that·OH,SO_(4)·-,O_(2)·-and1O_(2)all contributed to TC degradation in the UV/O_(3)/PDS process and exhibited a synergistic effect,which inhibited the generation of harmful products.In addition,the UV/O_(3)/PDS system can effectively degrade TC in a wide range of substrate concentrations and pH,and also showed excellent adaptability to various concentrations of anions(Cl-and HCO_(3)-).This study proves the feasibility of UV/O_(3)/PDS process for treating TC contaminated wastewater with complicated water matrix.

The co-removal of PCDD/Fs by SCR system in a full-scale municipal solid waste incinerator:Migration-transformation and decomposition pathways

Polychlorinated dibenzo-p-dioxins and furans(PCDD/Fs)generated from municipal solid waste(MSW)incineration are considered as the key pollutants,which could pose serious risks to the environment and ecology.This study comprehensively investigated the effect of selective catalytic reduction(SCR)system on PCDD/F removal,phase distributions,and migrationtransformation characteristics of 17 congeners in a full-scale MSW incinerator.The three flue gas samples and two fly ash samples were separately collected for PCDD/F analysis.The results showed that the SCR system reduced the I-TEQ concentration of PCDD/Fs from 0.135 to 0.010 ng I-TEQ Nm^(−3)with a remarkable toxicity removal efficiency of 92.6%,through oxidation decomposition over V_(2)O_(5)-WO_(3)/TiO_(2)catalysts and chlorination process of low-chlorinated congeners.In addition,the de novo synthesis observed along the flue between SCR system and stack regenerated unexpected PCDD/Fs,which might enhance the PCDD/F emission level.This study verified the three pathways of SCR system on PCDD/F removal and inspired operating suggestions for SCR system,i.e.,keeping SCR system operated in stable and consistent conditions,regularly replacing V_(2)O_(5)-WO_(3)/TiO_(2)catalysts,and timely cleaning the dusts and inlet materials of SCR system,which would be beneficial for achieving the ultra-low emission of PCDD/Fs in full-scale MSW incinerators.

Mechanism of MSWI Fly Ash Solidified by Microbe Cement

Microbe cement,a new type of gelling material,has attracted wide attention due to the increasing awareness of environmental protection.In this paper,the microbe cement in solidifying municipal solid waste incineration(MSWI)fly ash is investigated and the effect of the microbial induction method in solidifying MSWI fly ash is compared with the traditional chemical reaction strategy by characterizing the resulted calcite and the solidification productions with electronic universal testing machine,X-ray diffractometer(XRD),Fourier transform infrared spectrometer(FTIR),scanning electron microscope(SEM)and atomic absorption spectrometer.The results show that the MSWI fly ash solidified by microbe cement has the highest compressive strength while that of the chemical CaCO3 products is the lowest.The XRD results show that a new hydration gelling substance(Ca2SiO4·0.30H2O)is generated in the MSWI fly ash products.The FTIR results show that the frequency of Si-O bonds and C-O bonds in the products solidified by microbe cement has shifted,while there is no change occurred in the chemical CaCO3 products.The SEM results show that the microstructure of the products solidified by microbe cement is denser than that of chemical CaCO3 products.The test results of heavy metals show that the microbe cement could reduce the leaching concentration of heavy metals in MSWI fly ash.Ultimately,the leaching concentration of Pb meets the standard requirements,while that of Cd is still slightly higher than the standard requirement.

Assembly of SPS/MgSi assisted by dopamine with excellent removal performance for ciprofloxacin

In this work,magnesium silicate-based sulfonated polystyrene sphere composites(SPS/MgSi)were synthesized by one-step(SMD1)and two-step(SMD2)methods.For SMD1,MgSi particles were densely assembled on the surface of SPS,assisted by complexation between Fe^3+and hydroxyl phenol.For SMD2,SPS/SiO2 was firstly obtained by the same method as SMD1,and then SPS/SiO2 was transformed directly to SPS/MgSi under hydrothermal conditions.Therefore,MgSi obtained by the two-step method had an interwoven structure.Compared to SPS,MgSi and SMD1,SMD2 presented a larger specific surface area and more negative surface charges.Therefore,SMD2 showed superior adsorption performance toward CIP with concentrations of 5,10 and 50 mg/L,and for 50 mg/L,the equilibrium adsorption capacity could reach 329.7 mg/g.The adsorption process is fast and can be described by the pseudo-second-order kinetic model.The relationship between pH value and Zeta potential demonstrated that electrostatic interaction dominated the adsorption process.In addition,competitive adsorption showed that the effect of Na^+was negligible but the effect of Ca^2+was dependent on its concentration.Humid acid(HA)could slightly promote the absorption of CIP by SMD2.After five rounds of adsorption-desorption,the equilibrium adsorption capacity of SMD2 still remained at 288.6 mg/L for 50 mg/L CIP.Notably,SMD2 presented likewise superior adsorption capacity for CIP with concentrations of 10 and 50 mg/L in Minjiang source water.All the results indicated that this synthesis method is universal and that SMD2 has potential as an adsorbent for CIP removal from aquatic environments.