Chang-Geng Liu

The heterogeneous oxidation of SO2 by NO2 has been extensively proposed as an important pathway of sulfate production during haze events in China. However, the kinetics and mechanism of oxidation of SO2 by NO2 on the surface of complex particles remain poorly understood. Here, we systematically explore the mechanism and kinetics of the reaction bet...

Fenthion and parathion are two representative kinds of organophosphorus pesticides and widely used in agriculture. They are directly or indirectly released into the atmosphere by spraying or volatilization processes. However, their heterogeneous reactivity toward OH radicals has not yet been well understood. Therefore, this work investigated the he...

Secondary organic aerosol (SOA) plays a critical role in sustained haze pollution in megacities. Traditional observation of atmospheric aerosols usually analyzes the ambient organic aerosol (OA) but neglects the SOA formation potential (SOAFP) of precursors remaining in ambient air. Knowledge on SOAFP is still limited, especially in megacities suff...

Aerobic digestion is widely used to stabilize and reduce waste activated sludge in the decentralized wastewater treatment plants, but it would deteriorate sludge dewaterability. Thus, improving the dewaterability of aerobically digested sludge (AeDS) is of vital significance for sludge disposal and management. This study investigated the possibilit...

This work investigated the dewatering efficiency of aerobically digested sludge (AeDS) conditioned by peroxymonosulfate (PMS) activation with Fe²⁺ and citrate chelated-Fe²⁺ (Fe²⁺-Cit) as activators. The results showed that compared to Fe²⁺-PMS oxidation, Fe²⁺-Cit-PMS oxidation was more capable of improving AeDS dewaterability because of the strengt...

In this work, ultrasound (US) assisted zero-valent iron (ZVI)-activated peroxymonosulfate (PMS) oxidation was used to improve the dewaterability of aerobically digested sludge (AeDS). Capillary suction time (CST) reduction, centrifuged weight reduction (CWR), and water content of sludge cake (Wc) were determined to evaluate AeDS dewaterability. The...

Coniferyl alcohol derived from lignin pyrolysis, is a potential tracer for wood burning emissions, but its atmospheric stability toward OH radicals is not well known. In this work, the degradation kinetics of coniferyl alcohol by OH radicals was studied using a flow reactor at different OH concentrations, temperatures, and relative humidity (RH). T...

In this work, heat-activated peroxymonosulfate (heat-PMS) oxidation was used to condition waste activated sludge. The results showed that the optimal temperature and PMS dosage for sludge dewatering were 75 °C and 150 mg/g-volatile solids (VS), and the addition of rice husk (100–400 mg/g-VS) was favorable to further enhance sludge dewaterability. U...

Alkyl vinyl ethers are widely used as fuel additives. Despite this, their atmospheric chemistry and secondary organic aerosol (SOA) formation potentials are still not well known under complex pollution conditions. In this work, we examined the impact of SO2, relative humidity (RH), and particle acidity on the formation and oxidation state (OSc) of...

Gasoline evaporative emissions have become an important anthropogenic source of urban atmospheric volatile organic compounds (VOCs) and secondary organic aerosol (SOA). These emissions have a significant impact on regional air quality, especially in China where car ownership is growing rapidly. However, the contribution of evaporative emissions to...

2-Methoxyphenol (guaiacol) is derived from the lignin pyrolysis and taken as a potential tracer for wood smoke emissions. In this work, the effect of SO2 at atmospheric levels (0–56 ppbv) on secondary organic aerosol (SOA) formation and its oxidation state during guaiacol photooxidation was investigated in the presence of various inorganic seed par...

Guaiacol (2-methoxyphenol) has a high emission rate from wood burning and mainly exists in the gas phase, but the formation potential of secondary organic aerosol (SOA) from the atmospheric oxidation of guaiacol has not been well determined yet. In this work, SOA formation from the gas-phase reaction of guaiacol with OH radicals was investigated us...

Methoxyphenols are an important organic component of wood-burning emissions and considered to be potential precursors of secondary organic aerosol (SOA). In this work, the rate constant and SOA formation potential for the OH-initiated reaction of 4-allyl-2-methoxyphenol (eugenol) were investigated for the first time in an oxidation flow reactor (OF...

Gasoline evaporation emissions have become an important anthropogenic source of urban atmospheric VOCs and secondary organic aerosol (SOA). These emissions have a significant impact on regional air quality, especially in China where car ownership is growing rapidly. However, the contribution of evaporation emissions on the secondary aerosol (SA) is...

In this work, natural vanadium-titanium magnetite-activated peroxymonosulfate (VTM-PMS) oxidation coupled with rice husk (RH) as skeleton builder (VTM-PMS-RH) was employed to enhance sludge dewaterability for the first time. The optimal dosages of PMS, VTM, and RH were 200 mg/g total suspended solids (TSS), 1 g/g TSS, and 200 mg/g TSS, respectively...

Current atmospheric quality models usually underestimate the level of ambient secondary organic aerosol (SOA), one of the possible reasons is that the precursors at different concentrations may undergo different oxidation processes and further affect SOA formation. Therefore, there is a need to perform more chamber studies to disclose the influence...

2-Methoxyphenol (guaiacol) is derived from the lignin pyrolysis and taken as a potential tracer for wood smoke emissions. In this work, the effect of SO2 at atmospheric levels (0–56ppb) on secondary organic aerosol (SOA) formation and its oxidation state during guaiacol photooxidation was investigated in the presence of various inorganic seed parti...

Methoxyphenols are an important organic component of wood-burning emissions and considered to be potential precursors of secondary organic aerosols (SOA). In this work, the rate constant and SOA formation potential for the OH-initiated reaction of 4-allyl-2-methoxyphenol (eugenol) were investigated for the first time in an oxidation flow reactor (O...

In view of the merits of bioleaching and surfactant for sludge treatment, the possibility of surfactant with bioleaching pretreatment applied to improve sludge dewaterability was investigated in this work. The results showed that cetyl trimethyl ammonium chloride (CTAC) with bioleaching pretreatment was highly efficient in dewatering sludge. The op...

Methoxyphenols as the potential tracers for wood smoke emissions, are emitted into the atmosphere in large quantities but their atmospheric chemical behaviors have not been well characterized. In this work, heterogeneous kinetics of methoxyphenols in the OH-initiated reactions was investigated using a flow reactor under different experimental condi...

The potential of Fe(II)-activated peroxymonosulfate (Fe(II)-PMS) oxidation under mild temperature applied to pretreat waste activated sludge (WAS) was investigated in this work. The reciprocal ratio of capillary suction time to its initial value (CST0/CST) was used to characterize sludge dewaterability. The optimal conditions were Fe(II) 0.6 mmol g...

4-[(1E)-3-Hydroxy-1-propenyl)]-2-methoxyphenol (coniferyl alcohol) is a potential marker compound for wood smoke emissions in the atmosphere. In this work, the heterogeneous reaction of coniferyl alcohol adsorbed on silica particles with NO3 radicals was investigated. According to gas chromatography mass spectrometry (GC–MS) analysis, five products...

Methoxyphenols, as an important component of wood burning, are produced by lignin pyrolysis and considered to be the potential tracers for wood smoke emissions. In this work, the heterogeneous reaction between ferulic acid particles and NO3 radicals was investigated. Six products including oxalic acid, 4-vinylguaiacol, vanillin, 5-nitrovanillin, 5-...

In this study, a joint application of Fe(II)-activated persulphate oxidation and skeleton builders is used to condition sewage sludge for subsequent dewatering. The study mainly focuses on their efficacies and the optimization of the major operational parameters. The experimental results show that the joint application for conditioning sewage sludg...

Bioleaching combined with Fenton-like oxidation was used to condition sewage sludge. The results showed that it took approximately 1 d to decrease pH from 6.9 to 2.5 by bioleaching, with fixed sulfur power and FeSO4 x 7H2O dosages of 3 g x L(-1) and 8 g x L(-1), respectively. After bioleaching, the volatile solids(VS) reduction was 13.4%, and the s...

A novel joint method of bioleaching with Fenton oxidation was applied to condition sewage sludge. The specific resistance to filtration (SRF) and moisture of sludge cake (MSC) were adopted to evaluate the improvement of sludge dewaterability. After 2-day bioleaching, the sludge pH dropped to about 2.5 which satisfied the acidic condition for Fenton...

Organophosphorous pesticides (OPPs) are ubiquitous pollutants in the atmospheric environment with adverse effects on human health. In this study, heterogeneous kinetics of particulate phosmet and parathion with NO3 radicals were investigated with a mixed-phase relative rate method. A vacuum ultraviolet photoionization aerosol time-of-flight mass sp...

As a worldwide-used s-triazine herbicide, ametryn emits into the atmosphere in the both gas and particulate phases via spray drift from treatments and postapplication emissions, but its chemical degradation in the atmosphere has not been well characterized. In this study, heterogeneous kinetics of particulate ametryn with NO3 radicals is investigat...

Benzo[b]fluoranthene (B[b]F) and benzo[k]fluoranthene (B[k]F) are widespread priority pollutants of polycyclic aromatic hydrocarbons (PAHs), which can react with atmospheric oxidants during transport in the troposphere and lead to the formation of more toxic compounds. At present, the rates of heterogeneous reactions of B[b]F and B[k]F aerosols wit...

Lipid profiles of microorganisms, such as bacteria and fungi, have been studied intensively and have shown great potential for species differentiation. However, lipid profiles of basidiospores are seldom reported in the literature. In this study, the MALDI-TOF mass spectra of lipids extracted from basidiospores of Auricularia auricula, Agaricus bis...

Although heterogeneous reactions of polycyclic aromatic hydrocarbons (PAHs) with atmospheric oxidants may be important loss processes for PAHs, our understanding of their kinetics and products is incomplete. The study of heterogeneous reaction of suspended triphenylene particles with NO3 radicals is undertaken in a flow-tube-reactor. The time-of-fl...

In this study, MALDI-TOF lipid profiling was used as an experimental attempt to characterize pollen grains. Magnolia denudata, Lilium brownii var. viridulum, Pinus tabulaeformis, and Populus tomentosa pollen grains were collected as samples. The lipids in pollen grains were extracted by the methods of microwave-assisted formic acid digestion, micro...

Methoxyphenols, tracers for wood smoke, are emitted into the atmosphere with high quantities, but its chemical degradation in the atmosphere has not been well characterized. In this study, heterogeneous kinetics of particulate syringaldehyde (SA), vanillic acid (VA), and coniferyl aldehyde (CA) with NO3 radicals is investigated with a mixed-phase r...

Resmethrin, phenothrin, and fenvalerate are the synthetic pyrethroids that have been used widely against groundling or flying insect pests both indoors and outdoors. In this study, the heterogeneous reactions of the three pyrethroid particles with NO(3) radicals are investigated with a mixed-phase relative rate method. The reactions are performed i...

Pirimiphos-methyl (PMM) and pirimicarb (PM) are two typical N,N-dialkyl substituted pyrimidine pesticides. The heterogeneous reactions of suspended PMM and PM particles with NO3 radicals are investigated using an online aerosol time-of-flight mass spectrometer and a real-time atmospheric gas analysis mass spectrometer. Three products for PMM and fi...

Rapid identification of Bacillus spores has attracted great interest in the medical and forensic communities due to the highly pathogenic nature of certain Bacillus species and its potential application in bioweapons. In this study, we evaluated the feasibility of rapid and reliable identification of several Bacillus spp. (B. subtilis, B. cereus, B...

Polycyclic aromatic hydrocarbons (PAHs) and their derivates are mutagenic and carcinogenic substances widely distributed in the atmospheric environment. In this study, effective rate constants for heterogeneous reactions of NO(3) radicals with five 4-ring PAHs [benzo[a]anthracene (BaA), chrysene (Ch), pyrene (Py), 1-nitropyrene (1-NP), and 1-hydrox...

The rapid identification of bacteria is of increasing interest in food, biosafety, and clinical analysis. In this paper, we report a technique for rapid lipid profiling of bacteria by online droplet-deposited MALDI mass spectrometry. In the experiment, lipids in bacterial cells (Escherichia coli, Salmonella, and Bacillus subtilis) are extracted wit...

N,N-Dialkyl-substituted pyrimidine and N,N-dialkylaniline are basic structures for many pesticides. In this study, the heterogeneous reactions of O-3 with pirimicarb and isopropalin adsorbed on silica particles are investigated. The N-dealkylation and carbonylation of the N,N-dialkyl group have been observed as the important reaction pathways for b...

As an organophosphorous insecticide, phosmet is widely used for plant protection as well as against the ectoparasites on productive livestock. It emits into the atmosphere in both gas and particulate phases via spray drift from treatments and postapplication emissions, but its degradation in the atmosphere is not well-known up to now. In this study...

The heterogeneous reactions of typical polycyclic aromatic hydrocarbons (PAHs) and their derivatives (nitro-, oxy-, and hydroxy-PAHs) adsorbed on azelaic acid particles with NO3 radicals are investigated using a flow-tube reactor coupled to a vacuum ultraviolet photoionization aerosol time-of-flight mass spectrometer (VUV-ATOFMS). The mono-nitro-,...

Carbaryl, a widely used pesticide, can be released into atmosphere in the gas phase and condensed phase, but its atmospheric fate is not yet well understood. In this study, the reaction between suspended carbaryl particles and NO3 radicals is investigated, and the sequential nitration of carbaryl is observed in real time with a vacuum ultraviolet p...

Vinclozolin is a widely used fungicide that can be released into the atmosphere via application and volatilization. This paper reports an experimental investigation on the heterogeneous ozonation of vinclozolin particles. The ozonation of vinclozolin adsorbed on azelaic acid particles under pseudo-first-order conditions is investigated online with...

Bioleaching-dual polyaluminum chloride (PAC) and polyacrylamide (PAM) addition was used to condition sewage sludge. The results showed that FeSO4 x 7H2O addition improved the bioleaching rate obviously with a fixed sulfur power dosage of 3 g x L(-1); when the FeSO4 x 7H2O dosage was 8 g x L(-1), the bioleaching lasted 1.5 d to decrease the sludge p...