Search

Salinization is one of the major environmental problems threatening agricultural productivity. Soil salinization is defined as an excessive accumulation of salts within the soil profile. It negatively affects soil physical and chemical properties, as well as the biochemical ones. Reclamation of salt affected soils requires removal of soluble salts and Na+ from the soil exchange sites. Subsequently, salts are leached out the root zone by irrigation water when available. Gypsum (CaSO4·2H2O) is the most commonly used chemical amendment for reclamation of salt affected soils since it provides Ca2+ that replaces Na+ on the exchange sites and improves soil structure. Also organic amendments have been considered, but not extensively studied, for reclamation of salt affected soils. Recent studies have reported that biochar can be rich in nutrients like Ca2+ and Mg2+ and may enhance their availability in soil when added as amendment. Therefore, addition of biochar to a salt affected soil could aid in its remediation by supplying Ca2+ and Mg2+, and replacing Na+, improving aggregate stability and hydraulic conductivity. The objective of this study was to evaluate the effects of gypsum and biochar for the reclamation of a saline-sodic soil on some physical, chemical and biological properties. The topsoil of an Alfisol, about fifty meters far from the foreshore in the Petrosino coast (Sicily, Italy), was used for this experiment. The soil was air-dried and sieved at 2 mm. The main physical and chemical properties of the soil were: pH 7.3, clay 23 %, total carbonates 50.9 %, electrical conductivity 0.81 dS m-1 (1:5, w/v), total organic C 11.0 g kg-1, cation exchange capacity 24.8 cmol(+) kg-1, exchangeable sodium percentage 35 %. Two doses of gypsum (2.6 and 5.1 g kg-1 of soil) and two doses of biochar (4.2 and 8.3 g kg-1) were tested. The two doses of gypsum were calculated in order to decrease ESP from 35% to 25% and to 15%, respectively, whereas biochar was added in order to achieve an amount of 10 and 20 Mg ha-1. Following addition of gypsum and biochar, either alone or in combination, 100 g of soil were incubated at room temperature in 150 mL plastic pots and maintained at 50% of soil water holding capacity during all the duration of the experiment (22 days). One week after the incubation, three horse-radish seeds were sown. Then, after 13 days, plants were removed, oven dried at 60°C for 48 hours and weighed. The soils were analyzed to determine porosity, CEC, ESP, ECe, microbial biomass C, soil respiration and microbial community structure. The experiment was carried out in octuplicate. In this work, the results are reported and discussed

Aqueous salt solutions play an important role in nature because of their effects on environmental biogeochemical processes and on structural properties of biomolecules. Upon dissolution, salts split in ions that are solvated. Water in hydration shells is subjected to molecular motions that can be monitored by (1) H T1 NMR relaxometry. This technique allowed the evaluation of the nature of the interactions between water and ions via variable temperature experiments. Examination of relaxometry properties of aqueous solutions at variable salt concentrations allowed acknowledgement of the role played by ions in either structuring or destructuring water aggregates. A mathematical model has been applied on six environmentally relevant salts: NaCl, KCl, CaCl2 , CaCO3 , NaNO3 , and NH4 NO3 . It was linear only for the concentration dependence of KCl-R1 . This model accorded with the one reported in literature where it has been considered valid only for diluted solutions. However, in the present study, the range of linearity for KCl was extended up to the saturation point. The model was modified for NaCl, CaCl2 , and CaCO3 by using it as an exponential form in order to account for the nonlinearity of the R1 -versus-concentration curves. Nonlinearity was explained by the nonnegligible ion-ion interactions occurring as concentration was increased. Finally, further modification was needed to account for the asymmetric distribution of water around nitrate (in NaNO3 and NH4 NO3 ) and ammonium (in NH4 NO3 ). This study is preliminary to the comprehension of the diffusion mechanisms of ions in water solutions at the equilibrium condition with solid surfaces such as soils and biochar-amended soils. Copyright © 2014 John Wiley & Sons, Ltd.

Biochar is defined as charred organic matter applied to soil in a deliberate manner, with the intent to improve soil properties (Lehmann et al., 2009). Biomass-derived char can be used as energy carrier, as adsorber and as material for the improvement of soil properties. Carbonized organic matter can have different physical and chemical properties depending on the technology used for its production. Moreover char texture influences deeply physical and chemical properties. In this work effect of texture on the dynamics of a water saturated biochar was analyzed by FFC NMR. An industrial biochar derived from gasification of poplar wood was sieved to determine influence of texture on water dynamic on particles surface. Sieves with 2, 1 and 0.3 mm have been used to separate three different texture fractions. Each sample has been saturated with water and then analysed by FFC NMR relaxometry by applying a range of magnetic field from 40MHz to 0.01MHz. Three profiles with different longitudinal relaxation rate have been carried out. Sample with texture 1-2mm has a profile with the lowest longitudinal relaxation rate (R1). Profile of sample with textures

Anthropogenic activities alter the natural flow of materials and introduce novel chemicals into the environment thereby causing serious soil and water pollution. Indeed, many industries produce aqueous effluents containing toxic substances, especially heavymetals. The presence of these contaminants in the environment is a great issue because of their toxicityand bioaccumulation ability which affect human life and the environment. Various physicochemical and biological techniques have been used to remove the heavy metals from waste waters, including chemical precipitation, ion exchange, chemical coagulation, electrolytic methods, membrane processes, and adsorption. Biochar is a carbonaceous material obtained from the pyrolysis of plant and animal biomasses. Due to its high porosity, it could be a potential alternative to the existing conventional technologies for the removal and/or recovery of metal ions from aqueous solutions. The aim of this work was the chemical-physical characterization of biochar produced from chicken manure (CM), conifers and poplar wood wastes in order to assess their ability in the removal of heavy metal from aqueous solutions. Chemical-physical characterization of the different CM chars was conducted by cross polarization magic angle spinning (CPMAS) 13 C NMR spectroscopy and NMR relaxometry together with a comparative study between the removal efficiencies of Cu(II), Ni(II) andPb(II) from synthetic wastewater by using adsorption onto biochars surfaces. From adsorption studies, it was observed that conifer biochar did not significantly adsorbed metals. This behavior is probably due to his own chemical characteristics, since it’s quite hydrophobic and probably its surface lacks functional groups able to bind ions. Conversely, chicken manure biochar proved to have the highest removal efficiencies for all the metals considered, in the order Pb(II)>Cu(II)>Ni(II) ions. In conclusion, different chars have different physicochemical characteristics so they should be addressed to different uses. For example, conifer char should not be used for remediation since it’s not effective in removing inorganic metals from aqueous solutions. The most effective in remediation was chicken manure biochar, probably thanks to the presence of nitrogen on its surface. In fact, nitrogen has a free electronic doublet/pair able to interact with cation. Finally, char metals absorption involves both a physical and a chemical mechanism and further studies should be addressed to explain it.

Previous studies revealed that water molecules are hooked to biochar surfaces through unconventional hydrogen bonds (De Pasquale et al., 2012; Conte et al., 2013). Next question to answer is how metals can affect water mobility as they are adsorbed on biochar surface. To this aim, an orchard pruning char obtained by pyrolysis at 500°C was treated with solutions of Cu(II), Cr(VI) and Cu(II)+Cr(VI). Two different types of water can be recognized in BC. Namely, a fast relaxing water (T1 = 99 ms) is differentiated by a slow relaxing one (T 1= 233 ms). The former is made by molecules interacting with biochar surface through formation of the unconventional Hbonds previously identified (De Pasquale et al., 2012; Conte et al., 2013). The latter is made by water molecules freely slipping on the immobilized water layer. After metal adsorption, no changes were observed in MTBC relaxogram shapes as compared to BC relaxogram (Fig. 1). Moreover, all the MTBC relaxograms were similar to each other, regardless of the metal adsorbed on the carbonaceous material. Nature of the metal appears not to affect water dynamics on the porous material. The shortening of the T 1values in MTBC as compared to BC sample (from 99 to 42 ms, and from 23 to 95 ms, respectively) has been interpreted by two different molecular models. In the first case, a water layer may be immobilized on the metals directly adsorbed on MTBC surface (Fig. 2A). Since metal-water interactionscan be stronger than those in the untreated BC, the result is a shortening of the T1values from 99 to 40 ms. As a consequence, also the H-bonds between the immobilized water and the freely moving one can be strengthened, thereby leading to shorter T 1 value. The second molecular model considers metal ions bridging two water layers (Fig. 2B). The first water layer is immobilized directly on the surface of the porous material and it is bridged to the second water layer through the metal cation. Further investigations are needed in order to differentiate among the different models accounting for water dynamics on the surface of biochar treated with metal cations.

Char or biochar is a type of charcoal obtained from gasification/pyrolysis of biomasses. Instead of burning standing biomass from cleared forest, the resource is charred. The result is a highly porous, carbon-rich solid residue, really similar in appearance to the coal produced by natural burning. First considered an industrial waste, in recent years, the interest in this material has grown enormously given its ability to improve physical, chemical, biological and mechanical properties of soils, when used as amendment. However, its effects are highly variable depending onits chemical-physical properties which in turn depend greatly on the starting feedstock. The present study reports about the effects of different chars obtained from industrial thermo-chemical processes (gasification for energy production) on soil quality. In particular, radish germination was monitored using conifer, poplar and marc biochar as amendment. Results revealed that radish roots had different lengths depending on the nature of biomassesused to produce the different chars. Actually, the char produced from marc completely inhibited seeds germination. Moreover, to investigate the effect of the genotype, a study is going on regarding the influence of different biochars on seed germination of Troyer citrange [Citrus sinensis (L.) Osb. x Poncirus trifoliata (L.) Raf.].High resolution solid state NMR spectroscopy revealed no differences among the chemical nature of the different chars. Conversely, low resolution 1H fast field cycling NMR relaxometry showed that porosity of chars was directly related to the nature of the biomassesused for the thermo-chemical transformations. We can conclude that not all the chars can be applied to soil to improve its quality, thus a careful characterization must be carried out prior to field application in order to avoid counter-effects which can damage soil productivity.

La lignocellulosa è la più abbondante fonte rinnovabile per la produzione di bioetanolo. Sfortunatamente la produzione di biocarburanti liquidi da scarti lignocellulosici presenta molti inconvenienti a causa della compattezza e della complessità di questi materiali, caratteristiche che rendono molto più difficoltosa la loro degradazione enzimatica in zuccheri fermentabili rispetto ad altri biopolimeri come l’amido. Inoltre il costo della produzione di bioetanolo da biomasse lignocellulosiche è ancora molto alto rispetto a quello dei processi industriali che utilizzano come materiale di partenza l’amido. Obiettivo del presente studio è quello di testare su campioni di biomassa lignocellulosica un metodo di degradazione acida messo a punto sulla cellulosa microcristallina, al fine di ottenere zuccheri fermentabili per la produzione di bioetanolo. La biomassa utilizzata in questo studio è ottenuta dalla potatura di viti. Un’aliquota di biomassa viene posta in acido fosforico e riscaldata a 80°C per un tempo variabile nell’intervallo 15-300 minuti. Il supernatante viene separato ed analizzato mediante analisi colorimetrica per individuare la concentrazione di zuccheri riducenti. Il residuo solido viene prima lavato, poi seccato ed infine analizzato in spettroscopia CPMAS 13C NMR. Il risultato delle indagini colorimetriche ha mostrato che a circa 120 minuti si raggiunge il massimo della concentrazione di zuccheri riducenti. A partire da 150 minuti si osserva la diminuzione della concentrazione di zuccheri dovuta alla degradazione degli stessi come descritto già in Butera et al. (2011). Le analisi in spettroscopia CPMAS 13C NMR hanno messo in evidenza come il trattamento in acido fosforico consenta l’estrazione della cellulosa dalla biomassa solida. Infatti gli spettri NMR della componente solida dopo 60 minuti di trattamento contengono unicamente segnali di lignina. Questi risultati hanno trovato conferma nelle misure di rilassometria FFC NMR condotte sulla biomassa tal quale e sui solidi sottoposti ad idrolisi acida. Dopo trattamento con acido fosforico si osserva una diminuzione del T1(H) seguita da un progressivo aumento. La diminuzione è attribuibile al fatto che si ha depolimerizzazione dovuta all’idrolisi acida della cellulosa e dell’emicellulosa, i principali componenti delle biomasse lignocellulosiche. Man mano che si allontana il residuo polisaccaridico, si ottiene un innalzamento del T1(H) perché si «isola» la lignina altro polimero funzionale del residuo usato per questi esperimenti.

Anthropogenic activities alter the natural flow of materials and introduce novel chemicals into the environment thereby causing serious soil and water pollution Indeed, many industries produce aqueous effluents containing toxic substances, especially heavy metals The presence of these contaminants in the environment is a great issue because of their toxicity and bioaccumulation ability which affect human life and the environment Various physicochemical and biological techniques have been used to remove the heavy metals from waste waters, including chemical precipitation, ion exchange, chemical coagulation, electrolytic methods, membrane processes, and adsorption Biochar is a carbonaceous material obtained from the pyrolysis of plant and animal biomasses Due to its high porosity, it could be effectively used as a remediation tool to retain inorganic contaminants A comparative study between the removal efficiencies of Cu (II) and Ni (II) from synthetic wastewater by using adsorption onto biochars produced from chicken manure, conifers and poplar wood wastes was conducted to assess their ability in the removal of heavy metal from aqueous solutions The results showed that chicken manure biochar proved to have the highest removal efficiencies (up to 90% of removal) for both Cu (II) and Ni (II) ions The sorption ability of chicken manure biochars that underwent various degrees of carbonization (chars formed by pyrolysis at 350 and 500°C) was also investigated Higher pyrolysis temperatures lead to the disappearance of certain surface functional groups (e g , aliphatic) and the formation of others (e g , aromatic) These differences leads to a different adsorption behavior

Anthropogenic activities have produced numerous sites with extensive contamination close to residential areas. Several physicochemical and biological remediation methods exist for remediation of metal contaminated soils and lands, such as soil washing, soil flushing, phytoremediation, and electrokinetics. Biochar (biologically derived charcoal) is produced by pyrolysis of biomasses under low oxygen conditions, and it can be applied for recycling organic waste in soils. The main objectives of the present study were to determine the possible use of biochar from forest ersidues (Populus nigra) in order to achieve a stabilization of inorganic contaminants by adsorption processes. Adsorption of copper by biochar from dilute solutions showed a closer agreement with the Langmuir isotherm in a concentration range 25-500 mM. The decontamination by biochar is very suitable because the treatment is passive and does not require specialized equipment or extensive labor as compared to other remediation methods. Moreover, biochar is also a possible carbon sink due to its long term storage in environment, thereby favouring mitigation of the anthropic impact on environment.

Biochar is a carbonaceous material obtained by pyrolysis of biomass feedstocks. It is applied to soils in order to improve fertility and mitigate greenhouse-gases emissions. In fact, from the one hand, biochar changes physical-chemical soil properties, thereby affecting soil fertility. From the other hand, biochar is resistant to chemical and biochemical degradation. For this reason, its use allows carbon sequestration in soils and consequent reduction of carbon dioxide to the atmosphere. Here, dynamics of water at the liquid-solid interface of water saturated biochars is discussed. Results revealed that water dynamics is affected by the nature of biochar parent biomasses. Moreover, biochar chemical physical properties are affected by conditions for their production. It was understood that water undergoes to an inner-sphere interaction mechanism with biochar surface through formation of weak unconventional hydrogen bonds. Recognition of the interaction mechanisms between water and biochar is of paramount importance in order to understand why biochar soil amendments improve soil fertility and crop production.

In the last years, phosphoric acid has been increasingly considered as a simple and economic solvent for cellulose pretreatment before its degradation to glucose. Cellulose swells in 71–80% phosphoric acid solutions, whereas at higher H3PO4 concentrations dissolution appears to occur. In addition, it is reported that regenerated cellulose is more easily fermentable to bioethanol. The aim of the present study was to elucidate the mechanism for cellulose regeneration following treatment with phosphoric acid at room temperature. CPMAS 13C NMR spectra revealed a downfield shift of the 13C NMR signals from the regenerated cellulose as compared to the crystalline one. CPMAS 31P NMR spectroscopy showed presence of organic phosphate in the regenerated cellulose. These results suggested that cellulose regeneration consisted in the precipitation of a phosphorylated polymer. Fast field cycling NMR relaxometry confirmed such hypothesis. In fact, the correlation time of water saturated crystalline cellulose was shorter than that measured for the water saturated regenerated cellulose. The phosphate groups bound to the regenerated cellulose surface allow restriction of water mobility, thereby producing longer correlation times. Finally turbidimetric analyses revealed that the mechanism of regeneration consisted in a first reduction of the colloidal cellulose size followed by aggregation, colloidal size increment and flocculation. This study is of paramount importance to understand how phosphoric acid interact with cellulose in order to address its possible uses in biomass transformation for bioenergy purposes.

La pollina è tradizionalmente utilizzata in agricoltura come fertilizzante organico grazie al suo alto contenuto in nutrienti immediatamente disponibili per le piante (principalmente azoto, potassio e fosforo). Nonostante i vantaggi apportati alle colture, l’eccessivo uso della pollina come ammendante del suolo può causare gravi problemi ambientali, tra cui rischi per la salute umana e lisciviazione di nitrati o altri inquinanti nelle acquee sotterranee. Per diminuire i rischi legati al suo utilizzo, una soluzione alternativa potrebbe essere il ri-utilizzo energetico della pollina tramite la sua conversione in biochar. Il biochar è una sostanza carboniosa derivante dalla pirolisi di qualsiasi materiale organico. Grazie alle sue caratteristiche fisico-chimiche (elevata porosità, alto contenuto in carbonio e nutrienti), è risultato essere un ottimo ammendante dei suoli. Infatti ne aumenta la ritenzione idrica, la fertilità e la capacità di scambio cationico. Le proprietà fisico-chimiche del biochar sono però fortemente influenzate dalle condizioni di pirolisi, in particolare dalla temperatura massima raggiunta e dal tempo di residenza. Questo studio si propone di valutare l’influenza della temperatura di pirolisi e del tempo di residenza sulle proprietà fisico-chimiche del biochar prodotto da pollina. In particolare tre biochar sono stati ottenuti a 350°C, 450°C e 600°C. Il tempo di residenza in muffola è stato di 30min e 120min per ogni temperatura. Gli spettri CPMAS 13C NMR hanno mostrato che le caratteristiche chimiche dei biochar sono maggiormente influenzate dalla temperatura piuttosto che dal tempo di pirolisi. Tuttavia, indagini in risonanza magnetica nucleare a basso campo in rilassometria protonica (misure di T2 a campo fisso e T1 a campo variabile) hanno evidenziato che le proprietà superficiali dipendono anche dal tempo di pirolisi oltre che dalla temperatura. Questo studio ha dimostrato che la combinazione di più tecniche NMR (alto e basso campo, campo fisso e campo variabile) consente di riconoscere le differenze tra biochar ottenuti in condizioni differenti. La conoscenza della natura chimico-fisica del biochar in funzione dei processi con cui esso è ottenuto è fondamentale per la comprensione dei possibili usi tecnologici di questo nuovo materiale biosostenibile.