Ambient plasma treatment of pectin in aqueous solution to produce a polymer used in packaging.

Water resistance, mechanical behavior and coloration of pectin needs to be tuned for packing utilization. Plasma was used for the treatment of natural products, but there is no research on its effect on the biomass in the presence of ammonia. Though the reaction of pectin (PE) and ammonia was known to impart the ammonolysis and de-esterification, the plasma treatment on PE solution containing ammonia was explored to exemplify the amination and polymerization of the carbohydrate at the ambient condition. The plasma treatment increased the coloration of the solution due to the deprotonation of PE for the production of more sp2 carbon. The film from the amination of PE showed higher hydrophobicity and water stability than the bare PE. The plasma treatment alone decreased the Young's modulus (4.3 MPa versus 22 MPa), while the nitrogen addition enhanced the Young's modulus to 160 MPa and increased the tensile strength (28.7 MPa versus 25.8 MPa of PE). The hydrogen bonds from the amine group induced a glass-to-rubber transition at 77.9 °C by the increasing the crosslinking. This work provided a facile way of aminating and conjugating the biomass in solution to produce polymer with improved mechanical properties using plasma and ammonia incorporation.

Blue-light emitting aminated pectin for detecting Cu2+ ion.

This research studied the chemo-sensing of low-cost aminated pectin (PE) obtained by a facile calcination under ammonia gas at temperature no higher than 175 °C without excessive use of alkaline, acid or solvents. The ammonia gas was found to replace the hydroxyl and methoxyl group, enhancing the crystallinity and solubility of the resultant pectin than those calcined in air or in 5% H2. Though the increase of light absorption could be attributed mainly to the dehydration during calcination which caused the formation of CC double bond or aromatic ring, the N incorporation could be important to the photoluminescence (PL) emission. The PL quenching of the blue fluorescent aminated pectin showed a good linearity with the concentration of Cu2+, Fe3+ and the highest sensitivity toward Cu2+ among the investigated metal ions. In order to further increase the PL quenching toward Cu2+ and decrease the interference of Fe3+, a method involving H2O2 and ultraviolet illumination was developed to catalyze the oxidation of fluorophores on the polymer. This work provides new horizon on the modification and application of pectin in chemosensing.

Mechanized and Optimized Configuration Pattern of Crop-Mulberry Systems for Controlling Agricultural, Non-Point Source Pollution on Sloping Farmland in the Three Gorges Reservoir Area, China.

High-intensity utilization of sloping farmland causes serious soil erosion and agricultural, non-point source pollution (AGNSP) in the Three Gorges Reservoir Area (TGRA). Crop-mulberry systems are important agroforestry systems for controlling soil, water, and nutrient losses. However, there are many different mulberry hedgerow planting patterns in the TGRA. In this study, soil structure, nutrient buildup, and runoff nutrient loss were observed in field runoff plots with five configurations: P1 (two longitudinal mulberry hedgerows), P2 (two mulberry contour hedgerows), P3 (three mulberry contour hedgerows), P4 (mulberry hedgerow border), and P5 (mulberry hedgerow border and one mulberry contour hedgerow), as well as a control (CT; no mulberry hedgerows). P1 had the smallest percentage of aggregate destruction (18.8%) and largest mean weight diameter (4.48 mm). P5 led to the greatest accumulation of ammonium nitrogen (NH4+-N) and total phosphorus (TP) (13.4 kg ha-1 and 1444.5 kg ha-1 on average, respectively), while P4 led to the greatest accumulation of available phosphorus (AP), nitrate nitrogen (NO3--N), and total nitrogen (TN) (114.0, 14.9, and 1694.1 kg ha-1, respectively). P5 was best at preventing soil erosion, with the smallest average annual runoff and sediment loss of 112.2 m3 ha-1 and 0.06 t ha-1, respectively, which were over 72.4% and 87.4% lower than those in CT, respectively. P5 and P4 intercepted the most N in runoff, with average NH4+-N, NO3--N, particulate N, and TN losses of approximately 0.09, 0.07, 0.41, and 0.58 kg ha-1, respectively, which were 49.7%, 76.2%, 71.3%, and 69.9% lower than those in CT, respectively. P5 intercepted the most P in runoff, with average TP and total dissolved phosphorus (TDP) losses of 0.09 and 0.04 kg ha-1, respectively, which were 77.5% and 70.4% lower than those in CT, respectively. Therefore, the pattern with one mulberry hedgerow border and one mulberry contour hedgerow (P5) best controlled AGNSP, followed by that with only a mulberry hedgerow border (P4).

Evaluation of laboratory-scale in situ capping sediments with purple parent rock to control the eutrophication.

In this study, the effectiveness of controlling the eutrophication using purple parent rock to cap the sediments was evaluated in the laboratory scale. Sediments were collected from Sanxikou reservoir (China) in July 2013. Then, three types of purple parent rock (T1f, J3p, and J2s) which are distributed widely in southwest China were used to cap the sediments. Limestone and calcite were used as the contrast group, because they had been reported as effective controls on eutrophication. Then, they were incubated at 20 °C for 46 days. The results indicated that the application of purple parent rock as a barrier material can effectively inhibit the release of nutrient elements in sediments, and the inhibition rates of total nitrogen (TN), total phosphorus (TP), ammonium (NH4-N), and nitrate (NO3-N) were much better than that of limestone and calcite. Among the three types of purple parent rock, J3p exhibited the best inhibitory effect on the release of nitrogen in sediments, and the inhibition efficiency of TN, NH4-N, and NO3-N was 59.7, 77.6, and 45.1%, respectively. As for T1f, it exhibited the best inhibitory effect on the release of TP in sediments with the inhibition rate of 94.4%. Whereas all these capping materials showed weak inhibition on release of organic matter in sediments, and the inhibition efficiencies were less than 20%. Moreover, these treatments could also cause distinct changes in the microbial community in sediments and overlying water, and the contents of TN and TP in all capping materials increased. All results demonstrated that purple parent rock could inhibit the release of nutrient in sediments through mechanical interception, physical adsorption, and chemical absorption as well as changing the microbial activity in the covering layer, sediments, or overlying water.

[Influence of Spatial Pattern of Paddy Field on the Losses of Nitrogen and Phosphorus in Three Gorges Reservoir Area].

This paper used three plots of paddy field in Wangjiagou small catchment in Fuling District, Chongqing Municipality as a case study. Wangjiagou, located in Three Gorges Reservoir Area, provided a good case in terms of its closeness of surface runoff. The samples of individual rainfall of twelve times and process of two typical individual rainfalls on three plots of sloping paddy field were collected from 2014 to 2015. These samples were used to analyze the influence of spatial pattern of sloping paddy field on the concentration of nitrogen and phosphorus in the surface runoff. The samples of daily runoff in subcatchments in 2010 and 2015 were used to analyze the influence of spatial pattern change of subcatchments' paddy field on the concentration of nitrogen and phosphorus in the surface runoff. The results indicated that the removal rates of TN, NO3--N and TP of paddy field at the valley bottom were higher than those in the mid-slopes. The removal rate of TP would be higher if plot size of paddy field at the bottom got bigger. During individual rainfall event, the losses concentration of TN, NO3--N and TP in the paddy fields was significantly different among three different spatial patterns during the previous period of heavy rain event, but it became different during the next period of moderate rain event. The two subcatchments' spatial pattern change of paddy field had weakened the intercepting purification ability of nitrogen and phosphorus losses of paddy field in 2015, compared with that in 2010. TN's losses concentration increased significantly during the periods of light and moderate rain event and base flow. TP's losses concentration fluctuated during the event from moderate rain to heavy rain. Hence, increasing the area of paddy field of catchment and optimizing its spatial pattern reasonably were found as effective measures to control agricultural non-point source pollution in the Three Gorges Reservoir Region.

[Nitrogen Losses Under the Action of Different Land Use Types of Small Catchment in Three Gorges Region].

As an independent water-collecting area, small catchment is the source of non-point source pollution in Three Gorges Region. Choosing 3 kinds of the most representative land-use types and using them to lay monitoring points of overland runoff within the small catchment of Wangjiagou in Fuling of Three Gorges Region, the author used the samples of surface runoff collected through the twelve natural rainfalls from May to December to analyze the feature of spatial-temporal change of Nitrogen's losses concentrations under the influence of different land use types and the hillslopes and small catchments composed by those land use types, revealing the relation between different land-use types and Nitrogen's losses of small catchments in Three Gorges Region. The result showed: the average losses concentration of TN showed the biggest difference for different land use types during the period of spring crops, and the average value of dry land was 1. 61 times and 6.73 times of the values of interplanting field of mulberry and paddy field, respectively; the change of the losses concentration of TN was most conspicuous in the 3 periods of paddy field. The main element was NO3⁻-N, and the relation between TN and NO3⁻-N showed a significant linear correlation. TN's and NO3⁻-N's losses concentrations were significantly and positively correlated with the area ratio of corn and mustard, but got a significant negative correlation with the area ratio of paddy and mulberry; NH4⁺-N's losses concentrations got a significant positive correlation with the area ratio of mustard. Among all the hillslopes composed by different land use types, TN's average losses concentration of surface runoff of the hillslope composed by interplantating field of mulberry and paddy land during the three periods was the lowest, and the values were 2.55, 11.52, 8.58 mg · L⁻¹, respectively; the hillslope of rotation plough land of corn and mustard had the maximum value, and the values were 27.51, 25.11, 27.11 mg · L⁻¹, respectively; different land use types and spatial combination ways of subcatchment had a greater influence on TN's losses concentrations, so using a reasonable way to adjust land use structure and spatial arrangement of whole catchment was an effective measure to control the source of non-point source pollution of Three Gorges Region.

Spatial and temporal variations in non-point source losses of nitrogen and phosphorus in a small agricultural catchment in the Three Gorges Region.

Losses of agricultural pollutants from small catchments are a major issue for water quality in the Three Gorges Region. Solutions are urgently needed. However, before pollutant losses can be controlled, information about spatial and temporal variations in pollutant losses is needed. The study was carried out in the Wangjiagou catchment, a small agricultural catchment in Fuling District, Chongqing, and the data about non-point source losses of nitrogen and phosphorus was collected here. Water samples were collected daily by an automatic water sampler at the outlets of two subcatchments from 2012 to 2014. Also, samples of surface runoff from 28 sampling sites distributed through the subcatchments were collected during 12 rainfall events in 2014. A range of water quality variables were analyzed for all samples and were used to demonstrate the variation in non-point losses of nitrogen and phosphorus over a range of temporal and spatial scales and in different types of rainfall in the catchment. Results showed that there was a significant linear correlation between the mass concentrations of total nitrogen (TN) and nitrate (NO3-N) in surface runoff and that the relationship was maintained with changes in time. Concentrations of TN and NO3-N peaked after fertilizer was applied to crops in spring and autumn; concentrations decreased rapidly after the peak values in spring but declined slowly in autumn. N and P concentrations fluctuated more and showed a greater degree of dispersion during the spring crop cultivation period than those in autumn. Concentrations of TN and NO3-N in surface runoff were significantly and positively correlated with the proportion of the area that was planted with corn and mustard tubers, but were negatively correlated with the proportion of the area taken up with rice and mulberry plantations. The average concentrations of TN and NO3-N in surface runoff reached the highest level from the sampling points at the bottom of the land used for corn only, but lowest in rice fields. Slope gradient had a significant positive correlation with TN's and total phosphorus (TP)'s concentration losses. Concentrations of TN, NO3-N, and total phosphorus were significantly correlated with rainfall. Peak concentrations of ammoniacal nitrogen occurred during the fertilizer application period in spring and autumn. Different structures of land use types had a significant influence on the concentration losses of nitrogen and phosphorus; thus, using a reasonable way to adjust land use structure and spatial arrangement of whole catchment was an effective solution to control non-point source pollution of the Three Gorges Region.

Simulation of the dissolved nitrogen and phosphorus loads in different land uses in the Three Gorges Reservoir Region--based on the improved export coefficient model.

Nonpoint source pollution is one of the primary causes of eutrophication of water bodies. The concentrations and loads of dissolved pollutants have a direct bearing on the environmental quality of receiving water bodies. Based on the Johnes export coefficient model, a pollutant production coefficient was established by introducing the topographical index and measurements of annual rainfall. A pollutant interception coefficient was constructed by considering the width and slope of present vegetation. These two coefficients were then used as the weighting factors to modify the existing export coefficients of various land uses. A modified export coefficient model was created to estimate the dissolved nitrogen and phosphorus loads in different land uses in the Three Gorges Reservoir Region (TGRR) in 1990, 1995, 2000, 2005, and 2010. The results show that the new land use export coefficient was established by the modification of the production pollution coefficient and interception pollution coefficient. This modification changed the single numerical structure of the original land use export coefficient and takes into consideration temporal and spatial differentiation features. The modified export coefficient retained the change structure of the original single land use export coefficient, and also demonstrated that the land use export coefficient was not only impacted by the change of land use itself, but was also influenced by other objective conditions, such as the characteristics of the underlying surface, amount of rainfall, and the overall presence of vegetation. In the five analyzed years, the simulation values of the dissolved nitrogen and phosphorus loads in paddy fields increased after applying the modification in calculation. The dissolved nitrogen and phosphorus loads in dry land comprised the largest proportions of the TGRR's totals. After modification, the dry land values showed an initial increase and then a decrease over time, but the increments were much smaller than those of the paddy field. The dissolved nitrogen and phosphorus loads in the woodland and meadow decreased after modification. The dissolved nitrogen and phosphorus loads in the building lot were the lowest but showed an increase with the progression of time. These results demonstrate that the modified export coefficient model significantly improves the accuracy of dissolved pollutant load simulation for different land uses in the TGRR, especially the accuracy of dissolved nitrogen load simulation.

[Characterization of phosphorus forms in different organic materials].

The existing forms of phosphorus in seven organic waste materials including biogas residues of swine manure (ZZ), biogas residues of cattle manure (NZ), compost of cattle manure and corn straw (NJD), compost of sewage sludge (WD) and compost of rural daily garbage (NSLD) were characterized according to phosphorus fractionation procedures developed by DOU et al. The result showed that there was a great difference in the total phosphorus (TP) and the total phosphorus of various forms (P(t)) among different organic materials. ZZ had the highest content of TP with the value of 23.59 g x kg(-1); while NZ had the lowest TP content with the value of 3.61 g x kg(-1). The contents and proportions of phosphorus fractions in ZZ, NZ, NJD and WD followed the order of HCl-P > Residues-P > NaHCO3-P > NaOH-P > H2O-P, while followed the order of HC1-P > Residues-P > H2O-P > NaHCO3-P > NaOH-P in the three NSLDs. The proportion of HCl-P in the total fractionated phosphorus (P(tt)) in seven organic materials ranged from 47.75% to 84.96%, which indicated that most of P in organic materials existed in the forms that were easier to be extracted by strong extracting agents like HCl, which was difficult to be absorbed by plants. The inorganic phosphorus accounted for 79.72% -94.76% of the total phosphorus in the organic materials. Of all the phosphorus forms, the NaHCO3-P had the highest inorganic phosphorus fractions, but the inorganic phosphorus was mainly distributed in HCl-P. The organic phosphorus was mainly distributed in HCl-P and Residues-P. In addition, the higher proportions of inorganic phosphorus in NJD than those of NZ demonstrated that the composting process was benefit for the mineralization of organic phosphorus in organic materials and thus improving its availability.