Removal of Agrochemicals from Waters by Adsorption: A Critical Comparison among Humic-Like Substances, Zeolites, Porous Oxides, and Magnetic Nanocomposites

Abstract

The use of humic-like substances, zeolites, various porous oxides (i.e., Al, Fe, or Si oxides), and magnetic nanocomposites in the adsorption of agrochemicals from water was critically reviewed. Firstly, the adsorbents were characterized from the structural, textural, and physico-chemical points of view. Secondly, the fundamental aspects of the adsorption of various agrochemicals on the solids (dependence on pH, kinetics, and isotherm of adsorption) were studied and interpreted on the basis of the adsorbent features. Thirdly, iterative processes of agrochemical removal from water by adsorption on the reported solids were described. In particular, in some cases the residual concentration of agrochemicals in water was lower than the maximum concentration of agrochemicals that the Italian regulations allow to be released in wastewater, surface waters, or sink water.

Separation of Biological Entities from Human Blood by Using Magnetic Nanocomposites Obtained from Zeolite Precursors

“…Using the pairs of lowest/highest values of B and B, the following limiting values of the magnetic force F m on a single magnetic grain were obtained: for an average diameter of 7.5 mm (typical of grains existing in the two annealed samples obtained from A zeolite) [36] The reported values were all well above the typical value of the random forces of thermal origin acting on the grain at room temperature [42,43], so that the deterministic path of the grain by the effect of the magnetic field gradient was not disrupted by random thermal fluctuations.…”

“…Such thermal treatment gives rise to the reduction of a fraction of the exchanged iron ions to Fe 0 species and to the simultaneous structural collapse of the parent zeolite; the final product is a metal-ceramic nanocomposite, where nanoparticles of Fe 0 are dispersed within a ceramic matrix, which, in turn, still exhibits some irregular porosity, reminiscent of the parent zeolite matrix, and which mostly consists of amorphous silica and alumina, along with other Fe-containing phases, i.e., FeO x and Fe silicates, vide infra [29][30][31][32][33][34]. The same metal-ceramic nanocomposites, which have magnetic properties [29][30][31][32][33][34], were already successfully used for a broad range of applications, i.e., in the removal of agrochemicals from water by adsorption [35,36], as simulants of lunar agglutinates [37], and in the separation of Escherichia coli DNA from a crude cell lysate [38]. Indeed, the results obtained in [38] appeared particularly interesting for biomolecule separation, since the produced adsorbents were able to separate Escherichia coli DNA with a yield and an extraction efficiency that were about two or three times higher than those obtained by using a commercial system (GenElute Bacterial Genomic DNA kit from Sigma-Aldrich).…”

“…The above considerations and results triggered the present study, in which some of the metal-ceramic nanocomposites produced according to [29][30][31][32][33][34][35][36][37][38] were tested for some biological separations that are usually performed in molecular diagnostic laboratories. In particular, the produced magnetic adsorbents were used here for the separation of the target gene factors V and RNASE and of the Staphylococcus aureus bacterium from human blood samples.…”

Poly(β-cyclodextrin)-Activated Carbon Gel Composites for Removal of Pesticides from Water

“…Sorption processes and materials have wakened great attention being straightforward in application and often reusable, showing good efficiency and advantageous cost effectiveness. A wide range of adsorbent materials, including clays [ 15 ], alumina, mesoporous metal oxide [ 16 , 17 , 18 ] and zeolites [ 19 , 20 , 21 ], can be used for an extensive range of applications [ 22 ], albeit, activated carbon (AC) remains a most prominent material for environmental contaminants removal due to its high sorption efficiency. This includes the effective sorption of different pesticides as summarized in Table 1 .…”

New Insights in the Production of Simulated Moon Agglutinates: the Use of Natural Zeolite-Bearing Rocks

“…On the basis of these considerations, it was thought that the patented process, , proposed by some of us, aiming at obtaining metal–ceramic (where ceramic means inorganic, nonmetallic) magnetic nanocomposites from commercial zeolites, could be used to produce reliable moon dust simulants. The process envisages two steps, that is, a heavy-metal (Fe, Ni, or Co) cation exchange of a commercial zeolite and a thermal treatment at relatively mild temperatures (500–850 °C range) under reducing atmosphere (2.0 vol % H 2 in Ar). − The nanocomposites were already successfully used for other biochemical and environmental applications, and the same − efficient, inexpensive, and scalable synthesis method was used to obtain two nanocomposites containing Fe 0 nanoparticles embedded in a glassy matrix starting from two commercial zeolites, namely zeolite X and A …”