humification degree
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2022 ◽  
Vol 22 (1) ◽  
pp. 465-479
Author(s):  
Juanjuan Qin ◽  
Jihua Tan ◽  
Xueming Zhou ◽  
Yanrong Yang ◽  
Yuanyuan Qin ◽  
...  

Abstract. Water-soluble organic compounds (WSOCs) play important roles in atmospheric particle formation, migration, and transformation processes. Size-segregated atmospheric particles were collected in a rural area of Beijing. Three-dimensional fluorescence spectroscopy was used to investigate the optical properties of WSOCs as a means of inferring information about their atmospheric sources. Sophisticated analysis on fluorescence data was performed to characteristically estimate the connections among particles of different sizes. WSOC concentrations and the average fluorescence intensity (AFI) showed a monomodal distribution in winter and a bimodal distribution in summer, with the dominant mode in the 0.26–0.44 µm size range in both seasons. The excitation–emission matrix (EEM) spectra of WSOCs varied with particle size, likely due to changing sources and/or the chemical transformation of organics. Size distributions of the fluorescence regional integration (regions III and V) and humification index (HIX) indicate that the humification degree or aromaticity of WSOCs was the highest in the particle size range of 0.26–0.44 µm. The Stokes shift (SS) and the harmonic mean of the excitation and emission wavelengths (WH) reflected that π-conjugated systems were high in the same particle size range. The parallel factor analysis (PARAFAC) results showed that humic-like substances were abundant in fine particles (< 1 µm) and peaked at 0.26–0.44 µm. All evidence supported the fact that the humification degree of WSOCs increased with particle size in the submicron mode (< 0.44 µm) and then decreased gradually with particle size, which implied that the condensation of organics occurred in submicron particles, resulting in the highest degree of humification in the particle size range of 0.26–0.44 µm rather than in the < 0.26 µm range. Synthetically analyzing three-dimensional fluorescence data could efficiently reveal the secondary transformation processes of WSOCs.


2021 ◽  
Vol 13 (17) ◽  
pp. 9869
Author(s):  
Raffaele Morello ◽  
Francesco Di Capua ◽  
Ludovico Pontoni ◽  
Stefano Papirio ◽  
Danilo Spasiano ◽  
...  

The adoption of prolonged solid retention times during the biological treatment of urban wastewaters is a well-known strategy to reduce sewage sludge production. However, it also results in the production of a biological sludge with low percentages of biodegradable organic matter, also characterized by high humification degrees, which may hamper the anaerobic digestion treatment aimed at sludge stabilization. To accelerate the hydrolytic stage, the application of microaerobic conditions during the anaerobic digestion of low-biodegradable sewage sludge was investigated in this study. In particular, six bio-methanation tests of a real sewage sludge were carried out, introducing air in the bioreactors with doses ranging between 0 and 16.83 L air/kg VSin d, in order to evaluate the air dosage that optimizes the biomethane production and organic matter degradation. Notably, the lower air loading rates investigated in this study, such as 0.68 and 1.37 L air/kg VSin d, led to an increase in methane production of up to 19%, due to a higher degradation of total lipids and proteins. In addition, these microaerobic conditions also resulted in a decrease in the sludge humification degree and in lower volatile fatty acid accumulation.


Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4921
Author(s):  
Patrycja Boguta ◽  
Kamil Skic ◽  
Zofia Sokołowska ◽  
Magdalena Frąc ◽  
Lidia Sas-Paszt

The main goal of this work was to study the structural transformation of humic acids (HAs) under the influence of selected strains of fungi (Aspergillus niger and Paecilomyces lilacinus) and bacteria (Bacillus sp., Paenibacillus polymyxa and Bacillus amyloliquefaciens) with/without the presence of NPK fertilizers. Two-year experiments were conducted on two different soils and HAs isolated from these soils were examined for structure, humification degree, and quantity using fluorescence and UV-Vis spectroscopy, elemental analysis, and extraction methods. Results showed that the applied additives contributed to the beneficial transformation of HAs, but effects differed for various soils. HAs from silty soil with higher organic carbon content showed simplification of their structure, and decreases in humification, molecular weight, and aromaticity under the influence of fungi and bacteria without NPK, and with NPK alone. With both fungi and NPK, increases in O/H and O/C atomic ratios indicated an increase in the number of O-containing functional groups. HAs from sandy soil did not show as many significant changes as did those from silty soil. Sandy soil exhibited a strong decline in HA content in the second year that was reduced/neutralized by the presence of fungi, bacteria, and NPK. Periodically observed fluorescence at ~300 nm/450 nm reflected formation of low-molecular HAs originating from the activity of microorganisms.


2021 ◽  
pp. 0734242X2110359
Author(s):  
Feng Wang ◽  
Wu Yao ◽  
Weiwen Zhang ◽  
Lijuan Miao ◽  
Yifan Wang ◽  
...  

Aiming to reveal the humification process of organic waste and its contribution to the heavy metal behaviour affected by earthworm activity, it was studied about the variation of humic acid (HA) and heavy metal behaviour during vermicomposting of the mixed pig manure and 13C-labelled rice straw. The results showed that earthworms could well adapt to the culturing environment and feed organic matter for its growth and reproduction, the vermicomposting process increased the content of humic substances (HS), HA, and fulvic acid (FA) in substrate residues, but led to less transformation of HA into FA. The elemental, ultraviolet absorption spectroscopy, Fourier transform infrared (FTIR) and fluorescence excitation–emission matrix (EEM) analysis indicated that vermicomposting led to more aromatic structures and much higher humification degree in HA, whereas less protein, FA-like substances and plastein in HA. Vermicomposting could enhance the total Cu content and decrease Cu/Zn bioavailability in the substrate residues, and vermicomposting especially can help stabilize Cu in the substrate residues by forming more complexed HA–Cu.


Author(s):  
Mohamed Ahmed Mahmoud Mostafa ◽  
Abdel Samad Salem Ismail Hegazy ◽  
Osama Mohamed Fathy El-Sedfy ◽  
Zeinab Mostafa Abd El-Rhaman

<p>Laboratory study was performed to assess the impact of humification degree of humic acids isolated from composted rice straw (RS) and olive pomace (OP) on the metal loading capacity of extracted humic acids with Fe, Mn and Zn at different pH values (4, 5 and 6). The results revealed that the highest values of total acidity, carboxyl and phenolic-OH groups were achieved by HA-c extracted from compost C. Both HA-c and FA-c realized more pronounced values of total carbon and nitrogen content. Adversely, HA-c and FA-c achieved less pronounced values of oxygen and hydrogen as well as H/C, O/C and C/N atomic ratios. The loading capacity of Fe<sup>+2</sup> reached to optimum values at pH 5 for all studied humic acids. While the maximum loading capacity of Mn<sup>+2</sup> or Zn<sup>+2</sup> was achieved at pH 6. In this respect, the maximum loading capacity of Fe<sup>+2</sup>, Mn<sup>+2</sup> and Zn<sup>+2 </sup>were obtained for HA-c followed by HA-d.</p>


2021 ◽  
Author(s):  
Juanjuan Qin ◽  
Jihua Tan ◽  
Xueming Zhou ◽  
Yanrong Yang ◽  
Yuanyuan Qin ◽  
...  

Abstract. Water-soluble organic compounds (WSOC) are essential in atmospheric particle formation, migration, and transformation processes. Size-segregated atmospheric particles were collected in a rural area of Beijing. Excitation-emission matrix (EEM) fluorescence spectroscopy was used to investigate the sources and optical properties of WSOC. Sophisticated data analysis on EEM data was performed to characteristically estimate the underlying connections among aerosol particles in different sizes. The WSOC concentrations and average fluorescence intensity (AFI) showed monomodal distribution in winter and bimodal distribution in summer, with dominant mode between 0.26 to 0.44 µm for both seasons. The EEM spectra of size-segregated WSOC were different among variant particle sizes, which could be the results of changing sources and/or chemical transformation of organics. Size distributions of fluorescence regional intensity (region Ⅲ and Ⅴ) and HIX indicate that humification degree or aromaticity of WSOC was highest between 0.26 to 0.44 µm. The Stokes shift (SS) and the harmonic mean of the excitation and emission wavelengths (WH) reflected that π-conjugated systems were high between 0.26 to 0.44 µm as well. The parallel factor analysis (PARAFAC) results showed that humic-like substances were abundant in fine particles (< 1 µm) and peaked at 0.26–0.44 µm. All evidence supported that the humification degree of WSOC increased in submicron mode (< 0.44 µm) and decreased gradually. Thus, it was conjectured that condensation of organics still goes on in submicron mode, resulting in the highest humification degree exhibit in particle size between 0.26 to 0.44 µm rather than < 0.26 µm. Synthetically analyzing 3-dimensional fluorescence data could efficiently present the secondary transformation processes of WSOC.


2021 ◽  
Author(s):  
Hong-Yu Yang ◽  
Shu-Bo Zhang ◽  
Yue Zhao ◽  
Xin-Yu Xie ◽  
Zi-min Wei ◽  
...  

Abstract Background: Microbe is the driver for disposing of organic solid waste (OSW) during aerobic fermentation. Notwithstanding, the significance of microbe is always underestimated in numerous preceding studies about the aerobic fermentation products assessment. Results: Here, we investigate the humification degree (HD) and humic acid content could be assessed in terms of the bacterial community. Microbial sequencing and bioinformatics approaches are combined to analyze the biological characteristics of 105 aerobic fermentation samples collected. The bacterial communities could make predictions, which even correctly determines the categories of OSWs with 94% accuracy. Furthermore, the bacterial genera screened are designated as the bacterial code, which is substituted into the Random forest model to predict HD. And the bacteria codes can also provide a better prediction of the HD. Conclusions: Our result suggested that bacteria codes a reliable biological method is proposed to assess HD effectively. Our experiment not only proves that the aerobic fermentation can be revealed by biological means. The bacterial codes can also be used as an ecological and biological indicator to evaluate the quality of the aerobic fermentation of different materials. This study further provides new insights on the use of microbe to evaluate the content of various substances during the degradation process of OSWs.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marta Cybulak ◽  
Zofia Sokołowska ◽  
Patrycja Boguta

AbstractThere is limited information regarding the effect of biochar (BioC) on the fertility of fallow and grassland soils, as well as on the properties of their humic acids (HAs). The objective of this study was to evaluate with a 3-year field experiment the influence of BioC on the organic matter (OM) in Haplic Luvisol. BioC (obtained via wood waste pyrolysis at 650 °C) was applied to the soil of subplots under fallow and grassland at doses of 0, 1, 2 and 3 kg m−2. The soil samples were collected eight times. The physicochemical properties were determined for the soil and BioC by analysing the density, pH, surface charge, ash, and organic carbon content. Based on the changes in the structure of the HAs and their quantity in the soils, the chemical properties of the HAs were determined. The maximum BioC dose caused an increase in the content of Corg and HAs. BioC did not influence the humification degree coefficients of the HAs originated from fallow, whereas in the grassland, there were significant changes observed in these coefficient values, indicating that BioC may stimulate and accelerate the humification process of soil HAs. Increasing the BioC doses caused an increase in the soil’s HA content, suggesting an increase in soil sorption capacity. The fluorescence data showed BioC addition to the soil caused an increase in the number of structures characterised by low molecular weight and a low degree of humification.


RSC Advances ◽  
2021 ◽  
Vol 11 (46) ◽  
pp. 28476-28487
Author(s):  
Xinlin Wang ◽  
Yanbin Tong ◽  
Qigang Chang ◽  
Jianjiang Lu ◽  
Teng Ma ◽  
...  

Humic-like and protein-like components were identified by PARAFAC. THMs FP was significantly correlated with components C1 and C1 + C2. The source, types and humification degree of DOM affect the formation of DBPs.


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