Phosphorus recovery from aqueous product of hydrothermal carbonization of cow manure.

The work studies the recovery of nutrients (phosphorus and nitrogen) from the process water of acid-assisted hydrothermal carbonization (HTC) of cow manure. Three organic acids (formic acid, oxalic acid, and citric acid) and sulfuric acid were evaluated as additives in HTC. Using 0.3 M sulfuric acid, more than 99% of phosphorus and 15.6% of nitrogen from manure are extracted and dissolved during HTC at 170 °C with 10 min reaction time in a batch reactor. Nutrients (mainly phosphorus) were recovered through precipitation from process water by raising the ionic strength of the solution by addition of salts of magnesium and ammonia, and by raising the pH to 9.5. Subsequently, phosphorus-rich solids were recovered containing almost all (greater than 95%) of the dissolved phosphorus in the sulfuric and formic acid assisted runs. Morphology and qualitative chemical analysis of the precipitates were determined. It is shown by XRD that the precipitate formed from process water generated by HTC with oxalic acid is crystalline, although the diffraction pattern could not be matched with any expected substance.

Reusable TsOH-H2SO4 Mixed Catalysis for Tandem Synthesis of Biodiesel and Oxygenated Fuel Additives, tert-Butyl Glycerol Ethers.

A mixture of p-toluenesulfonic acid and sulfuric acid (TsOH-H2SO4) was used as a catalyst with a good performance in transesterification of palm oil (PO) with methanol and etherification of crude glycerol with isobutylene (tandem synthesis). For TsOH-H2SO4 catalyzed biodiesel production, the reaction noticeably ran faster in comparison with TsOH or H2SO4 alone and also gave up to 99.9% of the conversion using MeOH/PO molar ratio 9:1 at 80℃, in the period of 4 h. After the whole transesterification process, the crude glycerol phase was separated and then reacted with isobutylene in the etherification process using isobutylene/glycerol molar ratio 9:1 at 80℃, in the period of 5 h reaction time, to give DTBG and TTBG (91.14%). In the case of the etherification in biodiesel, higher selectivity of DTBG and TTBG (99.39%) was obtained in comparison with an absence of biodiesel as the solvent. Furthermore, the catalyst could be reused for 6 cycles of tandem synthesis (transesterification and etherification). The TsOH-H2SO4 catalyst showed a good catalytic performance in tandem synthesis similar to TsOH and it could be recovered for reuse while TsOH could not be recovered. This process offers an attractive route for reuse homogeneous catalyst of tandem synthesis, the main by-product of biodiesel, to tert-butyl glycerol ethers - a value-added in applications as a valuable fuel additive.

Preparation, characterization, antioxidant and anti-inflammatory activities of acid-soluble pectin from okra (Abelmoschus esculentus L.).

Currently, there are few studies on acid-soluble pectin from okra, especially in biological activity for antioxidant and anti-inflammatory. In this study, the antioxidant properties of acid-soluble okra pectin components and their anti-inflammatory were explored. Firstly, two acid-soluble okra pectic fractions, namely crude acid-soluble okra pectin (CAOP) and acid-soluble okra pectin (AOP), were obtained and exhibited structural and compositional variation. The two pectic fractions contained a low degree of esterification (42.0-46.5%) and a relatively high uronic acid content (31.6-37.3%). AOP was composed of galacturonic acid (79.1 mol/%), galactose (4.3 mol/%), rhamnose (14.5 mol/%) and xylose (2.1 mol/%), and the molecular weight was 92.8 kDa. Morphological and thermal properties of acid-soluble okra pectin components were also investigated. Compared to CAOP, AOP expressed better antioxidant activity, and suppressed the NO production in LPS-induced RAW 264.7 macrophages. All the above results indicated that AOP had the potential to act as a natural antioxidant or a functional anti-inflammatory food, which would broaden the development and utilization of okra resources.

Superfine pulverisation pretreatment to enhance crystallinity of cellulose from Lycium barbarum L. leaves.

Superfine pulverisation (SFP) pretreatment of Lycium barbarum L. leaves was performed to obtain highly crystalline cellulose. Compared with other common pulverisation methods, SFP enhanced cellulosic crystallinity by 18.3 % and 8.4 %, with and without post-acid treatments, respectively. XRD and solid-state NMR analyses showed that SFP facilitated the exposure of amorphous substances (i.e., hemicellulose and lignin) to NaOH and H2O2. Large amounts of silicon (5.5 %) and aluminium (2.1 %) were found to incorporate into the crystalline regions of SFP-produced cellulose. Further FTIR and thermogravimetric analyses revealed that SFP-produced cellulose contained large amounts of hydroxyl groups, affecting the cellulosic crystallinity and thermal stability. These findings demonstrate the potential for SFP to serve as a green technology for production of highly crystalline and mineral-rich cellulose.

Changes of nutrients and potentially toxic elements during hydrothermal carbonization of pig manure.

The effects of reaction temperature, residence time, sulfuric acid and potassium hydroxide on the total concentration and speciation of N and P, potentially toxic elements (salts and metal elements) of pig manure during its hydrothermal carbonization (HTC) were investigated. Concentrations of Cl, K, Na and Mg in the hydrochars were much lower but total N, P and nitrate-nitrogen (NO3--N) contents were significantly higher than in untreated pig manure. The acid-extractable fractions of Cu and Zn in hydrochars were 0.03-0.63 and 0.17-0.66 times lower than those in pig manure and decreased significantly with increasing reaction temperature. The addition of sulfuric acid (H2SO4) or potassium hydroxide (KOH) in HTC reduced the contents of P, Ca, Mg, Cl and heavy metal elements (HMEs) in hydrochars, and the removal rates of Cu and Zn were up to 55% and 59%, respectively. Overall, the rapid treatment of pig manure by HTC reduced the harm of salts and HMEs, and effectively recovered the nutrients in pig manure. The HTC under alkaline conditions was desirable for optimizing the main elemental composition of the hydrochars.

Bioremediation of gaseous methyl tert-butyl ether by combination of sulfuric acid modified bagasse activated carbon-bone biochar beads and Acinetobacter indicus screened from petroleum contaminated soil.

Combination of sulfuric acid modified bagasse activated carbon-bone biochar beads and Acinetobacter indicus screened from petroleum contaminated soil was the best condition for gaseous methyl tert-butyl ether (MTBE) removal. It was found that H2SO4 modified bagasse AC in powder form had higher adsorption capacity (989.33 mg g-1) than that in bead form (1.94 mg g-1). In addition, bone biochar in powder form (3.51 mg g-1) also had higher adsorption capacity than that in bead form (1.63 mg g-1). This was the fact that material beads contained high moisture content that inhibited the penetration of gaseous MTBE into the material. And a mixed material of H2SO4 modified bagasse AC-bone biochar beads had the highest adsorption capacity (2.22 mg g-1) compared to individual H2SO4 modified bagasse AC beads (1.94 mg g-1) and bone biochar beads (1.63 mg g-1) due to a mixed material had more rough surface and high surface area on its material. So, gaseous MTBE can penetrate through this material more easily. Although the maximum adsorption capacity of H2SO4 modified bagasse AC in powder form was the highest but microorganism cannot sustain and survive in this form for a long time. Therefore, the material beads were more suitable for microorganism to grow and degrade gaseous MTBE. Microorganism can degrade MTBE and caused no secondary wastes. Moreover, A. indicus was a novel strain for MTBE removal that has not been previously reported. Therefore, a combination of A. indicus-mixed material beads was a good choice for MTBE removal in a biofilter system.

Transition of cellulose supramolecular structure during concentrated acid treatment and its implication for cellulose nanocrystal yield.

Cellulose nanocrystals with cellulose I and II allomorphs (CNC-I and CNC-II) were prepared from eucalyptus cellulose I substrate by controlling the sulfuric acid hydrolysis conditions, including acid concentration (56-64 wt%), reaction temperature (45 or 60 °C) and time (10-120 min). The crystalline structures were verified by XRD and 13C-NMR. CNC-II only appeared at very restricted reaction conditions. The rapid cellulose supramolecular structure transition under sulfuric acid concentration of around 60 wt% resulted in an abrupt change in CNC yield. A maximal CNC yield of 66.7% was obtained at acid concentration of 58 wt% and reaction temperature of 60 °C. CNC-I exhibited spindle-shape, while CNC-II showed a twisted strip structure. The state of order in cellulose during the acid hydrolysis process has been studied using a coagulation method. A tentative model of CNC-I and CNC-II formation was then proposed. This work provided significant knowledge for the production of CNCs with high yield and controllable allomorph.

Effect-directed analysis by high-performance thin-layer chromatography for bioactive metabolites tracking in Primula veris flower and Primula boveana leaf extracts.

The genus Primula (Primulaceae) comprises species with high medicinal as well as ornamental values. Plants belonging to this genus are well recognized for their richness in bioactive constituents. The huge variety of secondary metabolites make their complete analysis impossible. In order to cope with this challenge, effect-directed analysis (EDA) via HPTLC coupled to structure elucidation techniques was applied on Primula species for the first time. As straightforward non-target bioanalytical technique, HPTLC-UV/Vis/FLD-EDA-ESI-HRMS hyphenates three different orthogonal dimensions, i.e. chromatography with spectrometric detection, biological/enzymatic assays and HRMS. The bioactive metabolites were determined in the middle polar extracts of two Primula species, P. veris (flower) and P. boveana (leaf). The bioactivity profiling comprised the antibacterial activity against Aliivibrio fischeri and Bacillus subtilis bacterial strains and acetyl-/butyrylcholinesterase (AChE/BChE) inhibition assays. The compounds were characterized and identified via their recorded spectral data (HRMS and 1H NMR). The results showed that linoleic and linolenic acids were the principle bioactive compounds present in the studied P. veris flower extract. In the P. boveana leaf extract, flavone, 2'-methoxy-, 2'-hydroxy- and 5,6,2',6'-tetramethoxyflavone (zapotin) were determined as active metabolites. The identification of zapotin, which was previously undescribed in the investigated plant, was considered as the strength of the straightforward non-target bioanalytical technique. Flavone turned out to be the highest potent metabolite, and at the same time, a multipotent compound referring to its various bioactivities discovered. An equivalency calculation of the HPTLC-AChE inhibition by flavone was performed with reference to the well-known inhibitor rivastigmine. As a result, the amount of flavone contained in 10.0 µg dry powder of P. boveana (corresponding to 0.1 µL extract) inhibited as strong as 4.5 µg rivastigmine. In other words, the flavone contained in P. boveana leaf extract powder turned out to be half as strong as the well-known AChE inhibitor rivastigmine.

Experimental study on radon exhalation behavior of heap leaching uranium ore column with dilute sulfuric acid.

In order to study the radon release behavior when heap leaching uranium ores with dilute sulfuric acid, unleached uranium ores from a uranium mine in southern China were selected as test samples. Adopting parameters from leaching processes commonly used in uranium mines, a laboratory experiment was carried out for 21 days with a one-dimensional acid heap leaching experimental column. The surface radon exhalation rate of uranium ore column was determined by static accumulation method while spraying with deionized water and dilute sulfuric acid. The uranium leaching rate and ore column height for all 21 days of the experiment were also measured. The results show that (1) when sprayed with a leaching agent, the surface radon exhalation rate of uranium ore column initially increased with time sharply. After a maximum value was reached, the rate gradually decreased and stabilized. When the spraying stopped, the surface radon exhalation rate of uranium ore column initially decreased, before increasing until it tended to stabilize. (2) During the entirety of the 21-day leaching experiment, the cumulative leaching rate of uranium increased gradually with time. On the other hand, the surface radon exhalation rate of uranium ore column fluctuated, but the leaching of uranium from uranium ores had almost no effect on the radon exhalation rate. (3) There was no linear correlation between the surface radon exhalation rate and the residual height of ore column during leaching, but the collapsing event of ore column was the direct inducing factor of the fluctuation of surface radon exhalation rate.

Investigation of corrosion inhibition effect and adsorption activities of Cuscuta reflexa extract for mild steel in 0.5 M H2SO4.

The corrosion inhibition nature of Cuscuta reflexa fruit extract, belonging to the family of Piperaceae, has been analyzed on mild steel in 0.5 M H2SO4 with the help of weight loss studies, potentiodynamic polarization, and electrochemical impedance spectroscopy techniques. The C. reflexa extract contains 3­methoxy­3,4,5,7­tetrahydroxy flavone, which decreases the corrosion rate of mild steel in acidic medium. The maximum corrosion inhibition efficiency was observed at 500 mg/L inhibitor concentration. The adsorption study of C. reflexa extract on mild steel surface has been conducted using UV, FTIR, AFM, SEM, and DFT.

Corrosion inhibition of mild steel in sulfuric acid solution by loquat (Eriobotrya japonica Lindl.) leaves extract.

The inhibition performance and mechanism of loquat leaves extract (LLE) for the corrosion of mild steel in 0.5 M H2SO4 were investigated using weight loss method, electrochemical measurements and scanning electron microscope (SEM). The results revealed that LLE acted as a modest cathodic inhibitor, its inhibition efficiency increased with the concentration of LLE and reached a maximum value of 96% at the 100% V/V concentration, but decreased with incremental temperature. Besides, it was found that the adsorption of LLE on steel surface obeyed Langmuir adsorption isotherm, and then the thermodynamic and kinetic parameters were further determined accordingly. Furthermore, LLE was preliminarily separated by pH-gradient sedimentation and the synergistic inhibition between the isolates was investigated.

Bio-succinic acid production from coffee husk treated with thermochemical and fungal hydrolysis.

Coffee husk (CH), a waste obtained from processing of coffee cherries via dry method, causes serious environmental problems. In this study, strategies were designed to utilize CH for succinic acid (SA) production. Three different CH hydrolysis methods: thermal, thermochemical and crude enzymes obtained by solid state fermentation of Aspergillus niger and Trichoderma reesei, were evaluated to generate fermentable feedstock for SA production using Actinobacillus succinogenes. The feasibility of these pretreatment methods was investigated. Accordingly, thermochemical hydrolysis using H2SO4 at 121 °C for 30 min, appeared the most effective method for CH hydrolysis, producing 24.4 g/L of reducing sugars (RS). Finally, 19.3 g/L of SA with yield and productivity of 0.95 g SA/g RS and 0.54 g/L/h, respectively, were obtained using CH hydrolysate. The current study revealed an alternative way of utilization coffee waste for value addition while mitigating environmental problems caused by its disposal.

Production of Biodiesel from Candlenut Oil Using a Two-step Co-solvent Method and Evaluation of Its Gaseous Emissions.

Candlenut oil (CNO) is a potentially new feedstock for biodiesel (BDF) production. In this paper, a two-step co-solvent method for BDF production from CNO was examined. Firstly, esterification of free fatty acids (FFAs) (7 wt%) present in CNO was carried out using a co-solvent of acetonitrile (30 wt%) and H2SO4 as a catalyst. The content of FFAs was reduced to 0.8 wt% in 1 h at 65°C. Subsequent transesterification of the crude oil produced was carried out using a co-solvent of acetone (20 wt%) and 1 wt% potassium hydroxide (KOH). Ester content of 99.3% was obtained at 40°C in 45 min. The water content in BDF was 0.023% upon purification using vacuum distillation at 5 kPa. The components of CNO BDF were characterized using a Fourier-transform infrared spectrometry and gas chromatography-flame ionization detector. The physicochemical properties of BDF satisfied the ASTM D6751-02 standard. The gaseous exhaust emissions from the diesel engine upon combustion of the BDF blends (B0-B100) with petrodiesel were examined. The emissions of carbon monoxide and hydrocarbons were clearly lower, but that of nitrogen oxides was higher in comparison to those from petro-diesel.

Silylation and characterization of microcrystalline cellulose isolated from indonesian native oil palm empty fruit bunch.

Silylation of microcrystalline cellulose (MCC), isolated from Indonesian native oil palm empty fruit bunch (OPEFB), using aminosilane compound synthesized through aminolysis of 3-glycidoxypropyltrimethoxysilane (GPTMS) with ethylenediamine (EDA) has been conducted in this study. Generally, there are three steps performed to isolate MCC before silylation process, i.e. bleaching, alkaline treatment and acid hydrolysis. All products resulted from bleaching, alkaline and acid hydrolysis treatments were characterized using Fourier Transform Infrared (FTIR) spectroscopy. Two conditions were optimized in this study which they were an acid concentration in hydrolysis process and aminosilane ratio in silylation process. The preliminary study regarding optimizing acid hydrolysis process by varying sulfuric acid concentration was obtained an optimum sulfuric acid concentration by 45% having highest crystallinity index (CI) measured using x-ray diffraction (XRD) data. The morphological structure of MCC was rod-like crystalline structure confirmed by transmission electron microscopy (TEM). The silylating agent was varied in this study with the ratio to MCC by 1:1, 3:1 and 5:1 mmol g-1. Based on loading analysis, the aminosilane with ratio 1:1 mmol g-1 was noted as optimum concentration having high loading yield by 79.2%. Effect of silylation on MCC properties was, on the one hand, it decreased the CI and crystallite size, however, on the other hand, it increased the surface area and pore volume.

Detection of coffee adulteration with soybean and corn by capillary electrophoresis-tandem mass spectrometry.

The detection of coffee adulteration with soybean and corn by capillary electrophoresis-tandem mass spectrometry was accomplished by evaluating the monosaccharides profile obtained after acid hydrolysis of the samples. The acid hydrolysis, using H2SO4 as a catalyst, increases the ionic strength of the sample impairing the electrophoretic separation. Therefore, Ba(OH)2 was used to both neutralize the medium and reduce the content of sulfate by precipitation of BaSO4. The best separation of nine determined monosaccharides (fucose, galactose, arabinose, glucose, rhamnose, xylose, mannose, fructose and ribose) plus inositol as internal standard was obtained in 500 mmol·L-1 triethylamine, pH 12.3. The monosaccharides are separated as anionic species at this pH. The proposed method is simple, fast (<12.0 min), present linear calibration curves (r2 = 0.995), and relative standard deviation for replicate injections lower than 5%. The LOQ for all monosaccharides was lower than 0.01 mmol·L-1, which is in accordance with the tolerable limits for coffee. Principal component analysis (PCA) was used to evaluate interrelationships between the monosaccharide profile and the coffee adulteration with different proportions of soybean and corn. Fucose, galactose, arabinose, glucose, sucrose, rhamnose, xylose, mannose, fructose, and ribose were quantified in packed roast-and-ground commercial coffee samples, and differences between adulterated and unadulterated coffees could be detected.

Physicochemical and in vitro antioxidant properties of pectin extracted from hot pepper (Capsicum annuum L. var. acuminatum (Fingerh.)) residues with hydrochloric and sulfuric acids.

BACKGROUND: Transformation of hot pepper residues to value-added products with concomitant benefits on environmental pollution would be of great value to capsicum oleoresin manufacturers. Pectin, a soluble dietary fiber with multiple functions, from hot pepper residues was investigated in this study. RESULTS: The extraction of hot pepper pectin using hydrochloric acid was first optimized using response surface methodology (RSM). The most efficient parameters for maximum hot pepper pectin yield (14.63%, dry basis) were a pH of 1.0, a temperature of 90 °C, an extraction time of 2 h and a liquid-to-solid ratio of 20 L g-1 . The pectin was mainly composed of uronic acids, and the major neutral sugars were galactose and glucose. The structure of hot pepper pectin was characterized by homogalacturonan and rhamnogalacturonan I elements. The physicochemical properties of hot pepper pectin extracted by sulfuric acid and hydrochloric acid were further investigated. The content of protein and degree of esterification in hot pepper pectin extracted with sulfuric acid solution (SP) were higher (P < 0.05) than those in that extracted with hydrochloric acid solution (HP), while the mean molecular weight of SP was lower than that of HP. Compared with HP, SP exhibited higher viscosity and better emulsifying property. CONCLUSION: Based on the yield and physicochemical properties of hot pepper pectin, hot pepper residues would be a new source to obtain pectin, and SP would be more preferred than HP. © 2017 Society of Chemical Industry.

Kinetic study of sulphuric acid hydrolysis of protein feathers.

Poultry feather keratin is the most important by-product from the poultry industry due to its abundance. Different methods have been still applied to process this by-product such as enzymatic hydrolysis which is expensive and inapplicable at the industrial level. This paper presents a study of acid hydrolysis of poultry feathers using different types of acids, sulphuric acid concentration, different temperatures and solid to liquid ratio to obtain a liquid product rich in peptides. The feathers analysis revealed a crude protein content of 88.83%. A maximum peptides production of 676 mg/g was reached using sulphuric acid, 1 molar acid concentration and 50 g/l solid to liquid ratio at a temperature of 90 °C after 300 min. A reaction scheme for protein aggregation and decomposition to polypeptides and amino acids was proposed and a kinetic model for peptides production was developed. The proposed kinetic model proved to be well adapted to the experimental data with R 2 = 0.99.

Effect of reaction solvents on the multi-scale structure of potato starch during acid treatment.

Potato starch was treated with 0.36% HCl in ethanol and water for various time periods, and its structural changes were evaluated and compared in this study. Acid-ethanol treated starch (AET-s) had relatively low average molecular weight (Mw) and z-average radius of gyration (Rg), and its solubility was higher than that of the counterpart acid-water treated starch (AWT-s). The granular appearance and differential scanning calorimetry (DSC) profile demonstrated that acid in ethanol and in water exhibited different attack pathways on the granules. No significant difference in crystallinity was observed for AET-s; however, the ratio of absorbance 1022/995cm-1 and the peak intensity detected by small-angle X-ray scattering (SAXS) were increased with increasing treatment time. These results suggested that ethanol-acid treatment simultaneously attacked on the amorphous and crystalline regions, and the degradation extent on crystalline regions caused by ethanol-acid treatment was higher than that observed by acid-water treatment.

Extraction and precipitation of phosphorus from sewage sludge.

Raw sewage sludge from East Rand Water Care Association (ERWAT) had high phosphorus (P) content, approximately 15.2% (w/w) P2O5, which indicates a potential resource for the limiting nutrient. Leaching sewage sludge with 1M sulphuric acid at 5% solid loading for 2h resulted in an 82% phosphorus extraction. However, the phosphorus was recovered as iron phosphates, thus a further purification step using ion exchange to remove iron was required to increase the degree of P release. Magnesium oxide and ammonium hydroxide were used as magnesium and nitrogen sources, respectively, as well as pH regulators to precipitate P as struvite. 57% struvite was precipitated and the total phosphorus content of the precipitate was 25.9%. Kinetic studies showed that the leaching of phosphorus follows the Dickinson model for the first 100min with a rate of reaction of about 2×10-5s-1. The rate limiting step is controlled by diffusion. Phosphorus solubility in 2% critic acid was almost 96%, which is the amount of phosphorus available to plants if the precipitate is applied as a fertiliser. Environmental, gram-positive Bacillus subtilis were found in the precipitate, which are harmless to the environment since they already exist in the soil where the precipitate can be applied as a fertiliser.

Yield, Esterification Degree and Molecular Weight Evaluation of Pectins Isolated from Orange and Grapefruit Peels under Different Conditions.

Orange (Citrus sinensis) and grapefruit (Citrus paradise) peels were used as a source of pectin, which was extracted under different conditions. The peels are used under two states: fresh and residual (after essential oil extraction). Organic acid (citric acid) and mineral acid (sulfuric acid) were used in the pectin extraction. The aim of this study is the evaluation the effect of extraction conditions on pectin yield, degree of esterification "DE" and on molecular weight "Mw". Results showed that the pectin yield was higher using the residual peels. Moreover, both peels allow the obtainment of a high methoxyl pectin with DE >50%. The molecular weight was calculated using Mark-Houwink-Sakurada equation which describes its relationship with intrinsic viscosity. This later was determined using four equations; Huggins equation, kramer, Schulz-Blaschke and Martin equation. The molecular weight varied from 1.538 x1005 to 2.47x1005 g/mol for grapefruit pectin and from 1.639 x1005 to 2.471 x1005 g/mol for orange pectin.