The aim of this work is to explore the suitability of the complementary use of mass spectra and the corresponding statistical analysis (principal components-Pareto analysis (PCA) and discriminant analysis (DA)) of these spectra to differentiate diverse humic samples as a function of their structural and conformational features. To this end, the mass spectra of humic samples belonging to the mai...

Decomposition of humic substances (HSs) is a slow and cryptic but non-negligible component of carbon cycling in sediments. Aerobic decomposition of HSs by microorganisms in the surface environment has been well documented; however, the mechanism of anaerobic microbial decomposition of HSs is not completely understood. Moreover, no microorganisms capable of anaerobic decomposition of HSs have be...

The present study examines the role of humic acid, as a representative of dissolved organic matter, in Cd(II), Cu(II), and Pb(II) speciation and biouptake by green microalgae. Cellular and intracellular metal fractions were compared in the presence of citric and humic acids. The results demonstrated that Cd and Cu uptake in the presence of 10 mg L(-1) humic acid was consistent with that predict...

Experiments in batch equilibrium system were carried out to evaluate the importance of physical and chemical factors determining the sorption efficiency of humic substances (HS) on aquifer material, which has been used for artificial recharge of groundwater (ARG) in drinking water production. Results showed that an increase of the amount of clay in the aquifer material and a decrease of pH in w...

abstract beneficial effects of humic substances on plant growth have been recognized by many researchers. a greenhouse experiment was conducted with humic acid (0, 20 and 50 mg/l) on lettuce cultivars ‘lollorossa’ and ‘javelina’ using completely randomized design at university of guilan. results showed that humic acid affected (p<5%) leaf number, height and nutrient uptake as well as ca, p and ...

The complex nature of natural organic matter (NOM), and the impact of this matter on drinking water quality have necessitated the characterization studies of NOM. A fluorescence technique for the characterization of NOM in Malaysian river water is reported. Water samples from several river sampling sites were collected and concentrated using a low-pressure reverse osmosis (LPROM). Solid phase e...

Optical properties of humic-like substances (HULIS) in biomass-burning aerosols A. Hoffer, A. Gelencsér, P. Guyon, G. Kiss, O. Schmid, G. Frank, P. Artaxo, and M. O. Andreae Max Planck Institute for Chemistry, Department of Biogeochemistry, Mainz, Germany Air Chemistry Group of the Hungarian Academy of Sciences, Veszprém, Hungary Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, Brazil...

For the first time, abundant natural carbon-based dots were found and studied in humic substances (HS). Four soluble HS including three humic acids (HA) from different sources and one fulvic acids (FA) were synthetically studied. Investigation results indicate that all the four HS contain large quantities of Carbon-based dots. Carbon-based dots are mainly small-sized graphene oxide nano-sheets ...