The influence of humic acids extracted from Chaouia soil on the behavior of transition metal ions and pesticides

      Humic acid (HA) and fulvic acid (FA) exist ubiquitously in environments and have a variety of functional groups, which allow them to complex with metal ions and pesticides. Furthermore, these interactions can not only alter the environmental behavior, but also influence the removal and transportation of those pollutants. The study of the interaction between Cu (II), VO (II) and Mn (II) with HAs provides environmental information on the oxidation states of paramagnetic metals and their mechanisms of binding to humic acids. Electron spin resonance (ESR) study demonstrates that VO (II) and Cu (II) ions are bound with oxygen ligands to HAs, while the Mn (II) complex occurs as [Mn(H2O)6]2+. Additionally, Cu (II) ions are more strongly bound than Mn (II) ions to soil HAs. The effect of the presence of HA on photolysis of Tribenuron-methyl (TRB) and Imazapyr (IMAZ) herbicides in water was studied by irradiation of different mixtures of HA/herbicide (0.5:1 and 1:1 by volume). The obtained results clearly demonstrate that HA substances exhibit a screening effect on the photochemical degradation of the two herbicides. The protective effect of HAs on the TRB and IMAZ degradation could be explained with an inclusion and/or adsorption of the herbicide molecules in the humic matrix

Characterization and hydration of cements and pastes obtained from raw mix containing Moroccan oil shale and coal waste as a raw material

In the present work, the hydration and physical properties of cements obtained from a raw mixes containing oil shale and coal waste as an alternative raw material were explored. A study of clinkers was carried out using chemical analysis and Rietveld analysis and the hydrated products were characterized by conduction calorimetry, X-ray diffraction, FTIR, Differential thermal analysis-thermal gravimetry and Scanning electron microscope. The findings showed that the cement paste containing both oil shale and coal waste had the highest compressive strength. According to the hydration studies, the four hydration steps were observed in all cements. The conduction calorimetry study showed the formation of the calcium monosulfoaluminate phase (AFm) in all cements which in cement containing coal waste was retarded by 50 h due to the high Na2O concentration in its clinker. Further, the identified hydration products: C-S-H gel, portlandite and Afm phase, which detected by XRD, FTIR and ATD/TG have been observed morphologically in SEM images. Moreover, the EDX microstructural study revealed that C-S-H gel contains a less amount of Aluminum and sulfur.This paper has been carried out as part of a CSIC-Mohammed V University of Rabat, cooperation programm (iCOOPA20067). Facilities given by IETcc (CSIC) and funding from BIA 2013-47876-C2-1-P and BIA BIA2013-43293-R projects as well as the Regional Government of Madrid Community and European Social Fund (Geomaterials Programme2 S2013/MIT-2914) are gratefully acknowledged.Peer reviewe

The influence of humic acids extracted from Chaouia soil on the behavior of transition metal ions and pesticides

Humic acids (HAs) exist ubiquitously in environments and have a variety of functional groups, which allow them to complex with metal ions and pesticides. Furthermore, these interactions can not only alter the environmental behavior, but also influence the removal and transportation of those pollutants. The study of the interaction between Cu (II), VO (II) and Mn (II) with HAs provides environmental information on the oxidation states of paramagnetic metals and their mechanisms of binding to humic acids. Electron spin resonance (ESR) study demonstrates that VO (II) and Cu (II) ions are bound with oxygen ligands to HAs, while the Mn (II) complex occurs as [ Mn(H2O)(6)](2+). Additionally, Cu (II) ions are more strongly bound to soil HAs than Mn (II) ions. The effect of the presence of HA on photolysis of Tribenuron-methyl (TRB) and Imazapyr (IMAZ) herbicides in water was studied by irradiation of different mixtures of HA/herbicide (0.5:1 and 1:1 by volume). The kinetic rate constant k of TRB and IMAZ decreases from 0.0029 h(-1) to 0.0012 h(-1) and from 0.242 h(-1) to 0.014 h(-1) in 0.5/1 HA/herb and 1/1 HA/herb respectively. The obtained results clearly demonstrate that HA substances exhibit a screening effect on the photochemical degradation of the two herbicides. The protective effect of HAs on the TRB and IMAZ degradation could be explained with an inclusion and/or adsorption of the herbicide molecules in the humic matrix