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An understanding of possible sources of ion generation in liquid crystal materials is of utmost importance to ensure uncompromised performance of modern liquid crystal devices. In this paper, time-dependent electrical properties of filled liquid crystal cells are used to reveal important information about often overlooked source of ion generation in liquid crystals. This source of ions originates from the ionic contamination of substrates of the liquid crystal cell. Ionic contaminants can be inherently present in the alignment layers or can be induced by external factors such as mechanical rubbing or irradiation with light. The model of this ion generation process is presented and tested using existing experimental data. [ABSTRACT FROM AUTHOR]

Ammonium and phosphate removal from industrial streams is important for many chemical processes, especially wastewater and sewerage treatment. Struvite precipitation is a popular choice and has been well characterized in model systems. However, struvite is a member of a family of similar phosphates of various valences and degrees of hydration. This paper shows that the ammonium phosphate precipitation from complex waste of decaying urine is identical to the product in model and other organic systems, i.e., struvite. We have shown that titration assays are possible for struvite, but they are difficult and hence we have also used nuclear magnetic resonance (NMR) and X-ray crystallography. NMR shows the high purity of struvite. Surprisingly, the crystals from this system are large and generate improved structural determination by X-ray crystallography compared to struvite prepared in solution or discovered in other natural systems. These large crystals allow facile separation of struvite, compared to more conventional methods using fluidized bed reactors which generate irregular concretions with difficulty. [ABSTRACT FROM AUTHOR]

On the basis of the principle of reaction continuous-flow quadrupole mass spectrometry, an automated sample preparation unit for inorganic nitrogen (SPIN) species was developed and coupled to a quadrupole Mass Spectrometer (MAS). The SPINMAS technique was designed for an automated, sensitive, and rapid determination of 15N abundance and concentration of a wide variety of N-species involved in nitrogen cycling (e.g. [image omitted] , [image omitted] , NH2OH etc.). In this paper, the SPINMAS technique is evaluated with regard to the determination of 15N abundance and concentration of the most fundamental inorganic nitrogen compounds in ecosystems such as [image omitted] , [image omitted] , and [image omitted] . The presented paper describes the newly developed system in detail and demonstrates the general applicability of the system. For a precise determination of 15N abundance and concentration, a minimum total N-amount of 10 μg [image omitted] - N, 0.03 μg [image omitted] - N, or 0.3 μ g [image omitted] - N has to be supplied. Currently, the SPINMAS technique represents the most rapid and only fully automated all-round method for a simultaneous determination of 15N abundance and total N-amount of [image omitted] , [image omitted] , or [image omitted] in aqueous samples. [ABSTRACT FROM AUTHOR]

The paper describes a field exposure system involving the application of growing chambers, ventilated with filtered or nonfiltered ambient air The diffusive resistance of primary leaves of beans (Phaseolus vulgaris L.), growing in medium with ammonium or nitrate as nitrogen source, has been used as indicator for low level air pollution, which does not produce visible leaf injury. In severely polluted atmosphere an addition of sodium chloride affected inversely the degree of injury. [ABSTRACT FROM AUTHOR]

Abstracts of original papers are presented including "Nitrogen Uptake and Ammonium N-Content of Flooded Soil in Direct-Seeded Rice Cultivation in Hokkaido" by Kanako Okada, Toshimi Kusume and Toshinari Igarashi, Effect of No-Tillage Direct Seeding of Rice Cultivation on the Cadmium Uptake by Rice Plants" by Yoshio Tokura and Naohiko Akai and "New Age of Plant Nutrition Research Through the Studies of Mycorrhizal Roots" by Yoshihiro Kobae, Hirokazu Toju and Satoshi Yamamoto.

Grey water has long been considered a promising option for dealing with water scarcity and reuse. However, factors such as lack of macronutrients and low carbon content make its treatment challenging. The aim of this paper was to investigate the applicability of sequencing batch reactor (SBR) technology to on-site grey water treatment at a sports centre for reuse in irrigation. The results demonstrated that the regenerated water complied with microbiological parameters concerning restriction of solids and organic matter removal. Denitrification was not fully accomplished, but ammonium was totally oxidised and low concentrations of nitrates were achieved. Effluent with good appearance and no odour was used in an experimental study to irrigate a grid system containing natural and artificial grass sections. The conclusion is that SBR technology offers a promising treatment for grey water. [ABSTRACT FROM PUBLISHER]

In this paper, we proposed a new approach for on-site colorimetric analysis of ferrous ions (Fe2+) and ammonium-nitrogen (NH4+-N) using a soil color meter as an alternative method to conventional spectrophotometry. The soil color meter we used can express solution color numerically on the basis of L*a*b* color space. After coloring of water by the 1, 10 phenanthroline method and the Indophenol blue method, the color of solution was measured by the soil color meter. A linear relationship between Fe2+and a* or b* values, and systematic change of NH4+-N with L* value, enable us to make a calibration curve. The Fe2+and NH4+-N concentrations in groundwater samples (Fe2+: 0.3–1.3 mg L−1; NH4+-N: 0.02–0.62 mg L−1) determined by the proposed method agreed well with those determined by conventional spectrophotometry with the difference being ± 0.05 mg L−1and ± 0.02 mg L−1, respectively. Since a similar apparatus is widely used in the soil science field, this technique would facilitate field surveys. [ABSTRACT FROM AUTHOR]

Concerns about possible health hazards arising from human consumption of lettuce and other edible vegetable crops with high concentrations of nitrate have generated demands for a greater understanding of processes involved in its uptake and accumulation in order to devise more sustainable strategies for its control. This paper evaluates a proposed iso-osmotic mechanism for the regulation of nitrate accumulation in lettuce (Lactuca sativa L.) heads. This mechanism assumes that changes in the concentrations of nitrate and all other endogenous osmotica (including anions, cations and neutral solutes) are continually adjusted in tandem to minimize differences in osmotic potential of the shoot sap during growth, with these changes occurring independently of any variations in external water potential. The hypothesis was tested using data from six new experiments, each with a single unique treatment comprising a separate combination of light intensity, nitrogen (N) source (nitrate with or without ammonium) and nitrate concentration carried out hydroponically in a glasshouse using a butterhead lettuce variety. Repeat measurements of plant weights and estimates of all of the main soluble constituents (nitrate, potassium, calcium, magnesium, organic anions, chloride, phosphate, sulphate and soluble carbohydrates) in the shoot sap were made at intervals from about 2 weeks after transplanting until commercial maturity, and the data used to calculate changes in average osmotic potential in the shoot. Results showed that nitrate concentrations in the sap increased when average light levels were reduced by between 30 and 49% and (to a lesser extent) when nitrate was supplied at a supra-optimal concentration, and declined with partial replacement of nitrate by ammonium in the external nutrient supply. The associated changes in the proportions of other endogenous osmotica, in combination with the adjustment of shoot water content, maintained the total solute concentrations in shoot sap approximately constant and minimized differences in osmotic potential between treatments at each sampling date. There was, however, a gradual increase in osmotic potential (i.e., a decline in total solute concentration) over time largely caused by increases in shoot water content associated with the physiological and morphological development of the plants. Regression analysis using normalized data (to correct for these time trends) showed that the results were consistent with a 1:1 exchange between the concentrations of nitrate and the sum of all other endogenous osmotica throughout growth, providing evidence that an iso-osmotic mechanism (incorporating both concentration and volume regulation) was involved in controlling nitrate concentrations in the shoot. [ABSTRACT FROM AUTHOR]

This paper focuses on the activity spectrum of three dimethylalkyl tertiary amines as potential active molecules and the corresponding ammonium salt-based antifouling (AF) paints. Bioassays (using marine bacteria, microalgae and barnacles) and field tests were combined to assess the AF activity of coatings. Bioassay results demonstrated that the ammonium salt-based paints did not inhibit the growth of microorganisms (except the dimethyldodecylammonium-based coatings) and that the tertiary amines were potent towards bacteria, diatoms, and barnacle larvae at non-toxic concentrations (therapeutic ratio, LC50/EC50, < 1). The results from field tests indicated that the ammonium salt-based coatings inhibited the settlement of macrofouling and the dimethylhexadecylammonium-based coatings provided protection against slime in comparison with PVC blank panels. Thus, results from laboratory assays did not fully concur with the AF activity of the paints in the field trial. [ABSTRACT FROM AUTHOR]

Landfill leachate is a concern in the wastewater field due to its toxicity, high ammonium and low biodegradable organic matter concentrations. The aim of this paper is to study the reliability of landfill leachate treatment using Sequencing Batch Reactor (SBR) technology for biological nitrogen removal. During the study the SBR pilot plant treated successfully 0.48 kg N·m-3 d-1 of urban landfill leachate. Furthermore, high nitrogen removal efficiencies (80%, on average) have been achieved by the operational conditions applied (step-feed strategy and alternating anoxic-aerobic conditions). [ABSTRACT FROM AUTHOR]

One of the important characteristics of the thermosetting resins such as urea-formaldehyde resin is the cure property. This is an invaluable characteristic for determining the processing capabilities of the resin. Differential scanning calorimetry (DSC) measurements are ideally suited to achieve this end. This paper presents the results of the effect of process variables on the enthalpy of cure of a low formaldehyde emission UF resin prepared by a four-stage process as described in the text. Response surface methodology (RSM) was used to design and the analyze the experiments. Urea (U) was added to the reaction mixture according to a pre-determined program of varying the number of additions and the duration between the additions during the second stage of the process. A mathematical relationship between the process variables and enthalpy of cure was established. The urea-formaldehyde (UF) resin was prepared under optimum conditions. Experiments were performed with the resin so prepared to determine the energy of activation of the curing reaction catalyzed by ammonium chloride. [ABSTRACT FROM AUTHOR]

The purpose of this paper was to study simultaneous removal of ammonia and potassium retained in wastewater by ion exchange with original and sodium conditioned zeolite after membrane treatment of anaerobically digested cattle manure effluents. Batch and column flow-through ion exchange tests were conducted to determine ion exchange capacity, pH effect, exchange kinetics, column runs and regeneration conditions. The exchange capacity of ammonium by original and sodium zeolite, according to the Langmuir equation, was 1.03±0.11 and 1.14±0.050 mmol/g, respectively. The kinetic experiments showed that the sorption of ammonium with coexisting K+ was rapid at the first 10 min, and approached equilibrium in 1 h. Ammonium removal was stable from lower pH to 9 and significantly decreased at pH > 10, while potassium removal was slightly increased at pH > 10. Column tests at a flow rate of 8.6-9.8 BV/h with a feed water containing 270 ppm of NH4+-N and 200 ppm of K+ showed that the total exchange capacity was approximately 8.8 mg/g for NH4+-N and 8.3 mg/g for K+. Both batch and column tests confirmed that zeolite had higher selectivity with potassium than with ammonium. On-column regeneration experiments showed that the exhausted zeolite could be efficiently regenerated by 5 BV brine solution containing 50 g/L NaCl and 0.2 M NaOH. The regenerated zeolite could be further reused for ammonium and potassium removal. [ABSTRACT FROM AUTHOR]

Plasma-induced polymerization of 2-methacryloyloxyethyl trimethyl ammonium chloride (DMC) was studied in this paper. The effects of discharge time and discharge power on tubular-type reactor chamber temperature were accurately tested using a on-line thermocouple, and it was found that the influence of discharge time and discharge power on temperature in a tubular-type reactor chamber accorded with the following equation: T = 15.935942 + 0.279195t + 0.200020P - 0.000595t2 + 0.004284t P + 0.005297P2, where T is temperature (°C), t is discharge time (s) and P is discharge power (W). We also found that temperature was very important for the properties of poly(DMC). For T ≥ 130°C, poly(DMC) was cross-linked, and the highest rate of water absorbed by poly(DMC) was 15 g/g. For T < 130°C, poly(DMC) was linear, and the highest intrinsic viscosity of poly(DMC) was 420.2 cm3/g. The optimal polymerization conditions of linear poly(DMC) were: discharge time 60 s, discharge power 60 W. [ABSTRACT FROM AUTHOR]

The work described in this paper presents an evaluation of disinfection by-products generation in four different biological treatment plant effluents, making use of sodium hypochlorite and sodium ferrate (IV) at varying concentration and reaction time. Correlations between pH, chemical oxygen demand, total organic carbon, ammonium nitrogen, combined chlorine and trihalomethanes (THMs) and haloacetic acids (HAAs) were carried out. Disinfection by-products generation presented a direct relation with concentration and sodium hypochlorite reaction time. For the highest hypochlorite concentration employed (20 mg L-1) and highest reaction time (168 h), the THMs total did not exceed 312.96 μg L-1, a value that lies below the Brazilian emission standard for treated effluents (1 mg L-1 of chloroform). The THMs presented an inverse correlation with ammonium nitrogen, when inverse (R2 = 0.646; P < 0.001) and exponential (R2 = 0.707; P < 0.001) function were used. As per HAAs this same relation was observed for logarithmic (R2 = 0.0397 P < 0.001) and exponential (R2 = 0.508; P < 0.001) functions. The more nitrified the effluent, the bigger the chlorinated disinfection by-product generation. The disinfectant sodium ferrate (IV) does not lead to halogenated by-product formation. [ABSTRACT FROM AUTHOR]

Polyaniline (PANI) was synthesized by oxidative polymerization of aniline using ammonium persulfate in an acid medium. The polyaniline salt was converted to base form by treatment with ammonium hydroxide. The polyaniline base was dissolved in N-methyl pyrrolidone (NMP) for film casting. The cast film was doped with HCl for obtaining higher conductivity. Both doped and undoped PANI films were characterized by UV-visible, FTIR, and XRD analyses. The electrical conductivity of the PANI film was studied by a four-point probe method at room temperature. Finally, ammonia gas-sensing characteristics of the prepared polyaniline film were studied by measuring the change in electrical conductivity on exposure to ammonia gas at different concentrations. The influence of concentration of acid during polymerization of aniline and dopant concentration on the gas sensing characteristics of PANI film are reported in this paper. [ABSTRACT FROM AUTHOR]

This paper reports a study of the extraction of 4-hydroxybenzoic acid with a mixture of trialkylmethylammonium chlorides (Aliquat 336) dissolved in a mixture of ShellSol T and ShellSol A. The experimental results revealed that the extraction of undissociated 4-hydroxybenzoic acid (HA) with Aliquat 336 (QCl) can be described by the following equation: ... while the extraction of anionic 4-hydroxybenzoic acid (A-) with Aliquat 336 is described by the following equation: ... The thermodynamic equilibrium constants in terms of the aqueous phase for the reactions above were evaluated to be, respectively, K02,ext = 10 (2.18+0.15) and K02,ext = 10 (0.81+0.11) at 298 K. The non-ideality of the aqueous phase was taken into account by applying a Setchenov equation for non-dissociated 4-hydroxybenzoic acid, the extended Debye-Hückel equation for dissociated 4-hydroxybenzoic acid, and the Pitzer model for other species in the aqueous solution. The use of K01,ext and K02,ext equilibrium constants allowed simulating the dependence of the distribution coefficient (D) on pH in the range 1.5-8.5. The equilibrium results showed that the presence of 1-decanol (ROH) in the organic phase complicates the extraction process. This can be explained by an interaction between QCl and ROH, which reduces the concentration of free QCl. The formation of QCl:ROH species in the organic phase was postulated and the correspondent equilibrium constant was found to be (3.3±0.3)/M. [ABSTRACT FROM AUTHOR]

This paper reports a study of the extraction of copper from ammonia/ammonium sulfate medium with LIX 54, aβ-diketone. The extraction of copper is very sensitive to the equilibrium pH. The highest extraction efficiency is attained in the range of pH 8–9.5. Above pH 10, the percentage of metal ion extracted decreases sharply. The extraction of copper by LIX 54 can be described by the following equation: The thermodynamic equilibrium constant was evaluated in terms of the aqueous phase and was found to be 10(2.89±0.03) M2 at 298 K. The nonideality of the aqueous phase was taken into account by applying the Pitzer model and the extended Debye-Hückel equation. The isotherms of extraction for the system copper/ammonia/ammonium sulfate/LIX 54 revealed that the increase in the salt concentration from 0.2 to 1 M makes the extraction process difficult. [ABSTRACT FROM AUTHOR]

In controlled N-nutrition experiments, differences in δ 15 N composition of leaves and roots are regularly found. In this paper we report results from a survey of nitrogen stable isotope signatures of leaves and roots of 16 plant species growing under natural conditions in a meadow and a forest understorey, which differed in nitrate and ammonium availability. Significant differences between leaf and root were observed. The range of Δ 15 N [leaf-root] values was -0.97 to +0.86‰, small compared to published values from controlled N-nutrition experiments, but almost as large as the range of leaf δ 15 N values (-1.04 to +1.08‰). Forbs showed the largest differences between leaves and roots and showed a significant difference with respect to habitat. Grasses and legumes did not show significant differences in Δ 15 N [leaf-root] between the two habitats. Care must be taken when using leaf δ 15 N values as representative for whole-plant 15 N composition in these two habitats. [ABSTRACT FROM AUTHOR]

This paper presents the pilot scale membrane separation studies on the Elmali Lake raw water in Istanbul, which is highly polluted by discharging of sewage waters. Low pressure nanofiltration (NF) and reverse osmosis (LPRO) membranes having the surface area of 2 m2 have been used during the experimental runs. Experiments were conducted at different pressures, temperature and pH ranges. Feed flow rate was about 300 L/h. As a result, flux values increased linearly with increasing pressure. Ammonia and nitrate ion rejections also increased with increasing pressure and characteristics of rejection were similar for the both types of membranes. Permeate flux value increased proportionally with the temperature. The temperature changing has also influenced the rejection rate of ammonia and nitrate ions. Both ammonia and nitrate ion rejections at neutral pH values were very high. Therefore, neutral pH value is suitable for TFC-S and TFC-HR membranes to remove ammonia and nitrate ions. [ABSTRACT FROM AUTHOR]

Waste rolling oil (WRO) can be regenerated by polymer flocculation-adsorption. Poly diallyl dimethyl ammonium chlorid (PDADMAC) is a linear high polymer with quaternary ammonium cations which was selected as an polymer flocculant. Effects of different treatment conditions on the performance of the recycled oil were investigated. Results indicated that the recycled oil achieved optimum quality under the following conditions: mass ratios of PDADMAC-WRO, KOH-WRO of 0.02 and 0.075, refining time, 20 min, refining temperature, 40 °C, stirring speed, 500 rpm, respectively. Compared with traditional regeneration methods, this flocculation method has higher effectiveness and can reduce the treatment time and cost. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of feeding silage to pigs on nitrogen (N) utilization and ammonia (NH3) volatilization. In total, 128 Yorkshire × Hampshire (30–110 kg) pigs were fed commercial feed (Control) or commercial feed mixed with dried, milled silage in pelleted form (Pellet-S), fresh, chopped silage (Silage-Ch) or intensively treated silage (Silage-Pr). Silage replaced 20% of the crude protein (g/kg). Diet affected daily N excretion, which was higher for pigs fed Silage-Ch and Silage-Pr than for pigs in the Pellet-S and Control treatments. Ammonium nitrogen (NH4-N) content in the manure and NH3 volatilization from fresh manure were higher for Control pigs than for pigs in the other treatments. Overall, these results show that pre-treatment of silage influences N utilization and excretion. Furthermore, the results indicate that feeding silage to pigs can reduce NH3 volatilization from fresh manure. [ABSTRACT FROM AUTHOR]

One of the practices which could mitigate the negative effects of drought stress is ammonium nutrition. Nitrification inhibitor (DMPP) can keep ammonium concentrations high in the soil for several weeks. Although there are contradictory reports regarding the priority of NH4+ uptake and its toxicity effects on wheat, it is necessary to understand better how to apply DMPP to increase drought tolerance without any negative effects. The field experiment was conducted using 15N trace technology. The fertilizers treatment included (15NH4)2SO4 and (15NH4)2SO4 with DMPP at four drought stress levels. Available soil mineral nitrogen was measured, as well as yield components and 15N recovery. The results showed that DMPP application at full irrigation and moderate drought stress caused an increase in grain yield of 13% and 10%, respectively. DMPP application at full irrigation, moderate and severe drought stress caused a significant increase in nitrogen use efficiency of 19%, 11%, and 17%, respectively. It seems DMPP application at the stem elongation stage, promoted NH4+ assimilation and transfer to the shoots, which has created relative resistance to drought stress conditions. In conclusion, it is recommended that farmers use DMPP at stem elongation to avoid wheat yield reduction and nitrogen recovery under drought stress. [ABSTRACT FROM AUTHOR]

A symbiotic microalgal-bacterial system may be an optional technology for wastewater treatment. It was composed of microalgae and activated sludge and established in the SBR to explore the effect of different dosing ratios of algae and sludge on the removal of nitrogen and phosphorus from simulated wastewater containing ammonium. It can be seen from the result that varied algae–sludge dosing ratios had a higher removal effect on COD removal, but the difference was not significant. The algal-bacterial symbiosis system had a 100% removal rate for ammonium removal on the 8th day. Relatively speaking, the removal of nutrients and related mechanisms vary with environmental conditions (inoculation rate). In general, when the additive ratio was 5:1 (algae: AS), the removal rate of TN and TP was the highest, reaching 53.85% and 85.13% in the shortest time (14 days), among them, the removal rate of ammonium and COD was 100%, and the reduction rates of Nitrite nitrogen and Nitrate nitrogen were 362.99% and 73.42%, respectively. In addition, 16S rDNA gene analysis results demonstrated that the microbial community in the reactor with algal sludge inoculation ratio of 5:1 had differences in three stages of the initial reaction, the middle reaction and the end of the reaction. Comamonadaceae, Flavobacterium, Paenarthrobacter, Mesorhizobium, Nitrobacter were enriched during the reaction operation. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) is involved not only in the regulation of plant growth, development, and stress responses but also in the regulation of plant-microbe interactions. Here, we demonstrate that Piriformospora indica can induce tobacco nitrate reductase to produce a NO signal in roots which enhances nitrogen uptake capacity by inducing the expression of ammonium and nitrate transporter genes and the development of lateral root and root hair, thereby promoting tobacco growth. In addition, the NO signal induced by P. indica is significantly different from that induced by the pathogen Phytophthora nicotianae. Inoculation with P. indica did not produce H2O2 and maintained high expression of Phytoglobin 1 in roots, resulting in a significantly lower NO level than in the roots inoculated with P. nicotianae. These findings suggest that an appropriate NO level is the likely basis of plant-P. indica symbiosis, which promotes the growth of host plants. [ABSTRACT FROM AUTHOR]

Nitrogen and water should be applied at the right time and amount to obtain optimum crop yield in arid and semi-arid regions. The study was carried out in 2017–2018 to investigate the effects of different supplementary irrigation levels applied after harvests, and different nitrogen sources on water use efficiency (WUE), yield and quality characteristics of sun-cured tobacco. The study included five different nitrogen sources (N1: zero-nitrogen, N2: ammonium nitrate, N3: ammonium sulfate, N4: calcium ammonium nitrate, and N5: urea) and four different irrigation treatments (I0:No irrigation; I33:66% deficit, I66:33% deficit and I100:100% full irrigation). The effects of nitrogen sources and supplementary irrigation treatments on plant height, leaf number, leaf width, leaf height, yield, quality grade, sugars, nicotine, phenolics, WUE and irrigation water use efficiency (IWUE) were statistically significant. Seasonal crop evapotranspiration values ranged between 117.7 and 235.3 mm. The highest WUE 1.65 kg m−3 and IWUE: 10.48 kg m−3 were recorded in I33 treatment. Plant characteristics were different between nitrogen sources; however, the results did not indicate a prominent nitrogen form. The results for supplementary irrigation revealed that the I100 treatment in semi-arid conditions increased the sun-cured tobacco yield by 22% with acceptable quality improvements. The gross income increased 1705 $ ha−1 with the increase in tobacco yield and sale price per hectare. [ABSTRACT FROM AUTHOR]

Ammonium (NH4+) oxidation is crucial for nitrogen (N) removal, contributing to regional and global N cycles, but is regarded as limited to a few biological pathways. A novel pathway for NH4+ oxidation and the N cycle is provided in the microbial anaerobic NH4+ oxidation coupled with Fe(III) (ferric iron) reduction, called ferric ammonium oxidation (Feammox). Over the past few years, Feammox, which results in significant loss of N in natural environments, has been detected widely in both terrestrial and aquatic ecosystems. Researchers have revealed various Feammox pathways, end products of nitrate (NO3-), nitrite (NO2-), and gaseous nitrogen (N2), and the interactions within the nitrogen and iron-cycle-related microbial communities, which might offer some novel alternative processes for wastewater treatment. However, there are substantial variations among different studies in terms of the key functional microorganisms. The underlying mechanisms of Feammox, as well as the effect of environmental factors, remain poorly understood. In this review of the emerging process, we detail the end-products and microbes involved in the Feammox process and discuss possible mechanisms and the main influential factors. In particular, we assess the potential applications in wastewater treatment based on previous experimental studies and highlight knowledge gaps and future research opportunities. [ABSTRACT FROM AUTHOR]

Catharanthus roseus belongs to the Apocynaceae family and is known as an important medicinal plant that produces several valuable terpenoid indole alkaloids. Reserpine is an indole alkaloid utilized in the treatment of paranoia, schizophrenia, and hypertension. In this study, we aimed to examine the effects of different concentrations of urea fertilizer and substrates on reserpine production by C. roseus plants. These plants were cultivated in pots containing either soil-humus-quartz, soil-perlite-quartz, or sand-quartz and treated with urea (60, 100, and 120 kg ha − 1) for 12 days. The experiment was performed based on a completely randomized factorial design with three replications. Different physiological parameters and reserpine concentrations were measured. Overall, results showed that the soil-humus-quartz substrate and 60 kg ha − 1 concentration of urea led to superior physiological and growth parameters (i.e., number of leaves, root length, root biomass, shoot length and shoot biomass) and the highest reserpine concentrations (605.8 ± 4.3 μg g − 1). It seemed that the soil-humus-quartz substrate contained organic materials and microorganisms which contributed to the generation of three nitrogen sources (i.e., urea, nitrate, and ammonium), enhanced the secondary metabolic pathways, and led to the highest production of reserpine in C. roseus plants. Supplemental data for this article is available online at https://doi.org/10.1080/11263504.2021.1986587. [ABSTRACT FROM AUTHOR]

Triethylammonium 2,4,14,16-tetrachlorodibenzo[g,j][1,3,6,12]tetraoxacyclotetradecane-2-phosphorodithioate was synthesized from bis(3,5-dichloro-2-hydroxyethoxyphenyl)methane by a two-step one-pot sequence. Its structure was confirmed by1H,13C, and31P NMR spectra, and elemental analysis. The X-ray diffraction analysis indicated that the molecules of the compound form an inclusion complex with chloroform molecules outside the phosphorus-containing macrocycle in the ratio of 1:2. [ABSTRACT FROM PUBLISHER]

It is effective to adsorb phosphate and ammonium from water by sludge-based biochar, while the desorption performance has not been studied systematically. Biochar in this study was prepared through the co-pyrolysis of sludge and walnut shells to remove N H 4 + and P O 4 3 − from water. The desorption characteristics of N H 4 + and P O 4 3 − from the post-adsorption sludge-based biochar were investigated. The effects of the adsorption condition (concentration of adsorption solution) and desorption conditions (pH value of desorption solution and desorption temperature and time) on desorption performance were examined. Several techniques were performed to characterise the properties of the post-adsorption sludge-based biochar. The adsorption amount of the pure sewage sludge biochar (SBC) for P O 4 3 − and the biochar derived from the co-pyrolysis of sewage sludge and walnut shell with the mixing ratio of 3:1 (MBC3-1) for N H 4 + were 14.19/ 23.75 mg/g and 9.28/ 16.23 mg/g, respectively, when the concentrations of the adsorbates were 100 and 500 mg/L. The desorption experiments showed that the acidic condition (pH = 2) was beneficial for P O 4 3 − and N H 4 + desorption. The highest desorption ratio reached 7.58% for P O 4 3 − and 2.18% for N H 4 + . The desorption of P O 4 3 − was endothermic, whereas that of N H 4 + was exothermic. The desorption amounts of P O 4 3 − and N H 4 + decreased and increased, respectively, with the increase in desorption time. This study of the desorption characteristics of P O 4 3 − and N H 4 + in sludge-based biochar provides a theoretical basis for the subsequent utilisation of sludge-based biochar. [ABSTRACT FROM AUTHOR]

A multipurpose filter in which sand and clinoptilolite are used together as filter material is suggested for the simultaneous removal of suspended solids and ammonium in one single unit. The capacity of the clinoptilolite used was determined as 10.4 mg/g for 20 mg/l initial ammonium concentration. In addition, a packed column ion exchanger with clinoptilolite and a classical sand filter were also investigated for comparison. Ammonium and suspended solids removal rates were observed and compared for all columns. The results of the column analysis have revealed that the ammonium removal rate, which was only 20% in the sand column, was increased to 100% by replacing 50% of the sand with clinoptilolite; similarly, the suspended solids removal, which was only 17% in the clinoptilolite column, was increased to 75% by replacing 50% of the clinoptilolite with sand. As such, when ion exchange and filtration processes were carried out in a multipurpose column, high removals for both parameters could be obtained simultaneously. Multipurpose columns could be an alternative both for the upgrading of existing treatment plants or for new plants for simultaneous removal of ammonium and suspended solids, giving considerable savings in terms of land requirements. [ABSTRACT FROM PUBLISHER]

The effects of ammonium hydroxide concentration and pH on the kinetics and reaction mechanism of oxidative ammonolysis of Repap organosolv lignin were studied. The reactions were carried out at 100 C with an oxygen pressure of 8 bar (116psi) and 0.4-1.6 M [NH4OH] and 9-12.7 pH. The resulting N modified lignins were analyzed for elemental composition and methoxyl group content. An increase in ammonium hydroxide concentration increased the rate of nitrogen incorporation, oxygen consumption, CO2 formation, and lignin dissolution. The rate of nitrogen incorporation was 0.5 order with respect to NH4OH concentration. The amount of oxygen consumed, oxygen incorporated into the lignin, CO2 formed, and OMe groups eliminated per mole of nitrogen incorporated decreased with increasing ammonium hydroxide concentration indicating that the increase in [NH4OH] accelerated nitrogen incorporation more than lignin oxidation. The dependence of the rate of nitrogen incorporation on the reaction pH went through a maximum leading to the conclusion that HO competes with ammonia in reactions with electrophilic lignin centers resulting in interruption of nitrogen incorporation into the lignin. [ABSTRACT FROM AUTHOR]

Derivatization procedures using quaternary ammonium hydroxides are now frequently applied to the gas chromatography/mass spectrometry (GCMS) analysis of paint media and varnishes. This paper compares the results obtained when triterpenoid resins are analysed using different reagents and sample preparation methods. Depending on the reagent and derivatization method used, the quaternary ammonium hydroxides produced multiple derivatives and induced isomerization in an number of the components of triterpenoid resins. This has implications for selecting an appropriate derivazition technique for the analysis of triterpenoid resins such as dammar and mastic. [ABSTRACT FROM AUTHOR]

4-Methyl- and 4,6-dimethylpyrimidines, methyl- and 2,5-dimethylpyrazines, as well as 3-methylpyridazine readily react with aromatic aldehydes in a hot solution of sodium hydroxide in the presence of a catalytic amount of a quaternary ammonium salt and in the absence of any organic solvent to yield the corresponding condensation products. [ABSTRACT FROM AUTHOR]

The aim of this work was to study the growth and nutrient removal efficiency of a mixed microalgal culture with and without the addition of low concentrations (0.5, 1, and 5 g L-1 of total liquid volume in the reactor) of natural zeolite. A control test in which only zeolite was added into a similar membrane photobioreactor was also conducted. The addition of 0.5 g L−1 zeolite to a continuously-fed membrane photobioreactor increased the microalgal biomass concentration from 0.50 to 0.90–1.17 g particulate organic carbon per L while the average ammonium removal efficiency increased from 14% to 30%. Upon microscopic inspection, microalgal cells were observed growing on the surface of zeolite particles, which indicates that zeolite can support attached microalgal growth. With higher zeolite doses (1 and 5 g L−1) inside the reactor, however, the breaking apart of added zeolite particles into finer particles dramatically increased solution turbidity, which likely was not beneficial for microalgal growth and ammonium removal due to reduced light penetration. This work shows that low doses of zeolite can be used as microcarriers to enhance microalgal biomass concentration and ammonium removal efficiency, while minimizing zeolite dose would likely reduce the turbidity effects. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa L.) is one of the most produced cereals in the world. Among the essential nutrients required by this crop, nitrogen (N) is of paramount importance to achieve optimum yields. In paddy fields, ammonium (NH4+) represents the main source of N. This work aimed to evaluate the root morphology, ammonium uptake kinetics and N accumulation in two upland rice varieties, Piauí and Manteiga from Maranhão – Brazil. The varieties were cultivated in hydroponic conditions and submitted to three different doses of ammonium: 1 – constant treatment with 0.2 mM NH4+, 2 – constant treatment with 1 mM NH4+ and 3 – constant treatment with 1 mM NH4+, followed by N starvation during 72 h and resupply with 1 mM NH4+. The varieties present contrasting behaviors when submitted to different doses of NH4+. Piauí showed higher biomass and root length under the treatment with 0.2 mM NH4+. The favorable kinetics parameters observed contributed to a higher N accumulation by Piauí in low dose of NH4+. Under 1 mM NH4+, a higher root biomass and favorable kinetics parameters was recorded by Manteiga. This variety presented a better performance with higher doses of N. Under the treatment of N resupply, Piauí variety showed to be more adapted, due to the greater root plasticity observed. For one hand, the results suggest that Piauí variety presents greater growth in environments with low dose or seasonal flux of NH4+. On the other hand, Manteiga variety presents better growth when submitted to higher levels of NH4+. [ABSTRACT FROM AUTHOR]

During the past two decades, interest has developed in regard to the possibility that plant roots can take up organic N compounds directly, a concept which challenges the conventional wisdom that soil inorganic N forms ( NH 4 + and NO 3 − ) are the sole primary sources of N absorbed by plant roots. We reviewed the literature based on single or dual (15N, 13C) stable isotope labelling techniques to test the hypothesis of direct uptake. Both isotopically enriched and natural abundance approaches were reviewed. Of the methods examined, the dual enrichment technique, when combined with compound specific and position-specific stable isotope analysis, provided incontrovertible evidence for direct uptake of simple amino acids. We demonstrate that dual labelling lacks overall sensitivity due to the high C concentration in plant tissue relative to N, and the higher natural abundance of 13C cf. 15N, which limits the period of measurement due to isotope dilution, and hence an assessment of the long-term contribution of direct uptake to the N economy of plant communities. [ABSTRACT FROM AUTHOR]

An attempted isolation of the elusive diammonium tetraoxidotungstate (NH4)2[WO4] as its imidazole (Im) adduct resulted in the serendipitous formation of hepta(ammonium) penta(1H-imidazol-3-ium) paratungstate B tetrahydrate having formula [NH4]7[ImH]5[W12O42]·4H2O (1). The synthesis, vibrational spectra, crystal structure and thermal study of the mixed cationic paratungstate tetrahydrate 1 are reported. The structure of 1 consists of a centrosymmetric paratungstate [W12O42]12– anion devoid of internal hydrogen atoms, which is charge balanced by ammonium and 1H-imidazol-3-ium cations. One of the four unique NH4+ cations and one of the three crystallographically independent 1H-imidazol-3-ium cations are disordered around a center of inversion. The cations, [W12O42]12– anion and the unique lattice water molecules are joined with the aid of five varieties of hydrogen bonding interactions. A comparative study of twenty-three partaungstates is described. Thermal decomposition of 1 results in the formation of monoclinic tungsten trioxide WO3. [ABSTRACT FROM AUTHOR]

Macroalgal growth in temperate coastal ecosystems is primarily regulated by light and inorganic nitrogen availability. The effect of light (photon irradiance) on NO3- and NH4+ uptake, and NO3- - assimilation, were studied in the red macroalga, Hemineura frondosa, which does not operate a carbon concentrating mechanism (non-CCM). Non-CCM macroalgae grow in low and high light environments but become increasingly dominant with depth, suggesting a mechanism for 'preserving energy' under low light levels. H. frondosa was acclimated to limiting (30 µmol photons m-2 s-1) and saturating (150 µmol photons m-2 s-1) irradiances for 8 days. Then, NO3- and NH4+ uptake rates were measured under limiting and saturating irradiances at six concentrations ranging from 2--64 µM. NO3- uptake did not follow saturating uptake kinetics at both irradiances suggesting multiple uptake mechanisms. NH4+ uptake saturated at concentrations <32 µM under limiting but not under saturating irradiance. Saturating irradiance resulted in greater maximum uptake rates of both NO3- and NH4+. There was no evidence that irradiance regulated NO3- reduction by nitrate reductase. Also illustrated is the importance of measuring nitrate reductase activity on fresh material, as freezing in liquid nitrogen and storage at -80°C for 7 days caused a 65% decline in activity. Photosynthetic pigments, soluble tissue nitrogen and % total tissue nitrogen were all higher in limiting irradiance. In this first study of the nitrogen physiology of a non-CCM seaweed, we show that light regulates NO3- and NH4+ uptake but not NO3- assimilation. [ABSTRACT FROM AUTHOR]

A study is reported of the adsorption mechanism of two ionic surfactants (sodium dodecyl sulphate and hexadecyl trimethyl ammonium bromide)on wool in relation to the temperature or time of treatment, either in aqueous or in aqueous-ethanotic media. From the results obtained, the effects of these ionic surfactants on acid and alkaline treatments of wool were evaluated by the alkali-solubility test, determination of the cystine content of the fibres, and analysis of the new amino acids formed during the treatment of wool fibres with methylamine or dimethylamine. [ABSTRACT FROM AUTHOR]

Quaternary ammonium random copolymers poly(methacryloyloxyethyl trimethyl ammonium chloride-co-acrylamide) P(DMC-AM) with either varied cationicities or intrinsic viscosities were synthesized and their structure was analyzed by FTIR and NMR; the results verified the structure of the P(DMC-AM). The rheological behavior of the P(DMC-AM) resulting from its polymer structure (cationicity and intrinsic viscosity) in NaCl aqueous solutions was studied. The results showed that increasing the polymer cationicity could enhance its salt resistance, especially at low cationicity, and the apparent viscosity was in direct proportion to the intrinsic viscosity of the P(DMC-AM) in salt solutions. Furthermore, salt effects (ionic radius, cationic valence, and anion valence) on the apparent viscosity were characterized. They clearly showed that the apparent viscosity was decreased with the increase of ion radius and ion valence. In particular, a difference in polymer aggregation was found when multivalent cations or anions containing solvents were added; two schematic models describing the rheological behavior of the P(DMC-AM) molecules in multivalent salt solutions are proposed. [ABSTRACT FROM AUTHOR]

A lysimeter experiment was carried out to investigate the effects of applying readily available carbon (12 or 24 t sucrose ha−1) to soil on nitrogen (N) losses from cattle urine patches. The carbon (C) was readily available to microbes and was applied onto intact soil monolith lysimeters, containing stony silt loam soil, beneath either ryegrass (Lolium perenne)/white clover (Trifolium repens) pasture (RG/WC) or lucerne (Medicago sativa). Cow urine (700 kg N ha−1) was applied in early July 2017, two days after C application. The application of readily available C increased the immobilisation of N in the soil which reduced the amount of soil mineral N. The C-induced immobilisation of N reduced the ammonia oxidising bacteria population growth rate and the amount of nitrate leached by 51–89%. The addition of readily available C had no significant effect on nitrous oxide emissions. These findings were consistent under both RG/WC and lucerne. [ABSTRACT FROM AUTHOR]

Micro/nano-structural polyaniline materials were prepared by using thin glass tubes as template in the presence of β2-SiW11Mn and ammonium persulfate, which were used as dopant and oxidant, respectively, in this system. The materials were characterized by IR, UV-Vis, XRD, TG-DTA and SEM techniques. The photocatalytic performance of polyaniline, β2-SiW11Mn and β2-SiW11Mn/PANI composite obtained was investigated using photodegradation of crystal violet as model reaction. The results showed that the photocatalytic activity of β2-SiW11Mn/PANI composite was much higher than polyaniline and β2-SiW11Mn due to a synergy between the two. The degradation rate of crystal violet was 91.19%. [ABSTRACT FROM AUTHOR]

Coastal wetlands and estuaries are impacted by nutrient loads from a variety of sources including infrequently occupied hunting and fishing camps. The marshland upwelling system (MUS) was designed to treat wastewater in the coastal environment where traditional septic systems or centralized wastewater collection and treatment are not viable. A laboratory macrocosm study was designed to simulate field conditions in which domestic wastewater is treated via injection into a marsh subsurface. Treatment of wastewater nitrogen (N) utilizing the MUS was examined under high (∼20 ppt) and low (∼2 ppt) salinity conditions. Two N wastewater solutions were used, one treatment consisted of 100 mg NH4-N L−1, while a second treatment consisted of 80 mg NH4-N L−1/20 mg NO3-N L−1. The 20 ppt salinity treatment was found to have a negative impact on NH4-N sorption. The potentially mineralizable N rate was higher in the low salinity treatment, which could potentially be offset by the higher sorption capacity at lower salinities. The background salinity of the local groundwater should be considered as the salinity will play a role in the longevity of the system. [ABSTRACT FROM AUTHOR]

The supply of exogenous nitrate to nitrate-depleted plants transiently changes the expression of nitrate-responsive genes within minutes. In addition to this so-called primary nitrate response, nitrate is suspected to play a long-term regulatory role, acting as a nitrogen (N) status signal for the entire plant. In our recent study using Arabidopsis thaliana, the manipulation of the internal nitrate levels independently of internal organic N without external N indicated that nitrate accumulation in the shoot alone causes genome-wide responses systemically, including the induction of nitrate assimilation genes and repression of N starvation-inducible genes. These responses mimic high nitrate growth situations for plants, suggesting that shoot nitrate acts as a N satiety signal. On the other hand, it is widely known that external supply of ammonium as another major N source also triggers N-rich responses, which led us to hypothesize that the existence of external ammonium may interfere with the genome-wide responses regarding shoot nitrate satiety. To clarify this, we compared transcriptional responses to shoot nitrate satiety with and without external ammonium both in Arabidopsis shoots and roots. Further, in order to determine the major role of nitrate satiety signaling, we extracted those genes regulated by shoot nitrate level regardless of the presence or absence of external ammonium and annotated them by two independent enrichment analyses. Here, we show that genome-wide transcriptional responses to shoot nitrate satiety are significantly lowered in the presence of external ammonium especially in the shoot. A major component for the ammonium-dependent attenuation of the nitrate satiety responses comprised a set of genes encoding the machinery for translation, glucosinolate biosynthesis, and photosynthesis. On the other hand, the nitrate satiety responses commonly observed irrespective of the presence/absence of ammonium included the components for translation and nitrate assimilation, whose transcriptional responses could be mediated partly via NIN-LIKE PROTEIN (NLP), NITRATE-INDUCIBLE GARP-TYPE TRANSCRIPTIONAL REPRESSOR1 (NIGT1), and cytokinin signaling on the basis of our transcriptional profiling and cytokinin determination. [ABSTRACT FROM AUTHOR]

This study was carried out to investigate the effects of salt (60 mM NaCl) in nigella (Nigella sativa L.) amended with different nitrogen (N) forms. Plants were grown for 2 weeks under hydroponic conditions in the presence of 3 regimes of nitrogen: nitrate (NO3−) alone, ammonium (NH4+) alone, or the mixture of NO3− and NH4+ combined or not with 60 mM sodium chloride (NaCl). Results indicated that N. sativa performs much better when fed with 2.5: 0.00 mM and 1.25: 1.25 mM NO3−: NH4+, than the other ratios. NaCl addition reduced chlorophyll concentration regardless of N source. In the absence of NaCl, photosynthesis rate was more important in exclusively NO3− amended plants than other ratios. NaCl restricted transpiration and stomatal conductance, excepting in 00: 2.5 NO3−/NH4+-feed plants. As compared to their respective control, the nutrition of NO3− feed plants was more affected by salt than that of NH4+-feed ones. Na+ was less accumulated in the tissues of plants amended with NH4+ than if fed with NO3−. This behavior could maintain the ratio of K+/Na+ in the shoot of NH4+-fed plants. NaCl increased the antioxidant activity independently of nitrate/ammonium ratio. The considerable advantage of NH4+ nutrition under salt could be related with high production of total phenolic compounds and flavonoids. Hence, we showed that Nigella sativa was more sensitive to salt if cultivated in the presence of NO3−/NH4+ ratio higher than 1. NH4+ alleviates NaCl-induced stress by the reduction of the Na+ accumulation in the organs and an increase in antioxidative responses. [ABSTRACT FROM AUTHOR]

Anaerobic ammonium oxidation (anammox), a promising technology for bio-nitrogen removal, has been a research hotspot in the field of leachate treatment. However, the inhibitory effect of organic matter and high-strength nitrogen on anammox bacteria and the limitation of the theoretical total nitrogen removal efficiency of anammox (<90%) are obstacles to its wider application. The mechanisms of the inhibitory effects of organic matter, ammonium, and nitrite on anammox bacteria, and the corresponding control strategies are summaries. The anammox-based processes developed for advanced nitrogen removal (ANR) in recent years, including anammox-based heterotrophic denitrification, anammox-based partial denitrification, and anammox-based constructed wetlands are systematically discussed. An integrated anaerobic system of simultaneous denitrification and methanogenesis (anaerobic membrane bioreactor) + anammox-based processes was proposed for the ANR and optimal energy recovery from leachate. This process showed a 16% increase in biogas yield, a 64% decrease in aeration energy consumption, and the decrease in the external carbon source is expected to be 100% compared to conventional leachate treatment processes such as anoxic/oxic-membrane bioreactors. Finally, a few research perspectives on leachate treatment using anammox-based processes are reviewed. The conclusions drawn from the studies presented herein provide guidance for further research and engineering applications in the field of leachate treatment. AnMBR pretreatment is proposed for energy recovery and elimination of inhibition of anammox bacteria by organics. Anammox-based heterotrophic denitrification, partial denitrification, and anammox-based constructed wetlands are discussed for ANR. SDM is proposed for ANR from leachate via anammox effluent recirculation. An SDM(AnMBR)+anammox based process is proposed for energy saving and recovery. [ABSTRACT FROM AUTHOR]

The metabolic and kinetic behaviour of a nitrification process in the presence of 2-chlorophenol (2-CP) was evaluated in two sequencing batch reactors (SBR1, SBR2) inoculated with nitrifying sludge previously exposed to phenolic compounds. The SBR1 was inoculated with sludge previously exposed to 2-CP, while the SBR2 was inoculated with sludge previously exposed to p-cresol. An inhibitory effect of 20 mg 2-CP-C/L on both nitrification processes was observed, as specific rates decreased according to a control assay in the absence of 2-CP. However, the inhibitory effect decreased throughout the cycles. At the end of cycle 6, a stable nitrifying process was observed with the sludge previously exposed to 2-CP (SBR1), as an ammonium consumption efficiency and a nitrate production yield close to 99.6 ± 0.3% and 0.99 ± 0.02 were respectively achieved. Despite a complete ammonium consumption being achieved with the sludge previously exposed to p-cresol (SBR2), partial nitrification was observed as nitrate production yield accounted for 0.28 ± 0.08 and nitrite was accumulated within the culture. Nevertheless, both nitrifying sludges had the ability to completely consume 2-CP. The use of SBR systems with nitrifying sludge previously exposed to 2-CP resulted in a better nitrification performance, thus it may be a good alternative for achieving a stable nitrifying respiratory process where complete and simultaneous ammonium and 2-CP consumption can be acquired. [ABSTRACT FROM AUTHOR]

Sequential diffusion techniques used to speciate inorganic nitrogen-15 (15N) during soil or water analysis are complicated by incomplete recovery of ammonium (NH4+)-N, introducing error in the subsequent determination of nitrate (NO3–)-N. Based on studies to evaluate different strategies for minimizing cross-contamination error in Mason-jar diffusions, a simple cleaning technique was developed that involves an additional 6-h diffusion using 0.6 M boric acid (H3BO3) at room temperature following the recovery of NH4+-N. This technique was 60–87% effective for reducing cross-contamination of unlabeled NO3–-N by labeled NH4+-N and became more effective for controlling analytical error with decreasing sample volumes, lower NH4+-N enrichment, and larger quantities of NO3–-N. When used with the cleaning technique described, sequential diffusions were far superior for 15N analysis of NO3–-N, as compared to the nonsequential approach that involves an isotope dilution calculation after separate diffusions to determine NH4+-N and total mineral N. [ABSTRACT FROM AUTHOR]

This study investigated the potential of removing ammonium () from aqueous solutions using corncob based on modified biochar (MBCC) in the fixed-bed column. Corncob biochar was soaked in a mixture of HNO3 6.0 M and NaOH 0.3 M to prepare active binding sites for ammonium removal. The effect of initial ammonium concentrations (10-40 mg/L), flow rates (1-9 mL/min) and MBCC fixed-bed heights (8-24 cm) on the breakthrough characteristics of the adsorption system were studied. The results showed that the highest adsorption capacity of fix-bed column, the breakthrough time and value of Ct/Co were 12.83 mg/g, 480 min and 0.862 ± 0.025 at 10 mg/L of initial ammonium concentration, 8 cm of MBCC fixed-bed height and 3 mL/min of flow rate, respectively. The breakthrough curve model in this study also indicated that all Yoon-Nelson, Thomas and Adam-Bohart models well fit with the experimental data with a high R2. The results also proved that MBCC can be used as a potential adsorbent for eliminating in the fixed-bed column. The saturated MBCC was also regenerated and reused consecutively for four cycles. The usage of mixture of NaOH and NaCl in recovering MBCC was better than NaCl only. [ABSTRACT FROM AUTHOR]

Plant growth requires mineral nutrients from soil environment. It is important for plant to develop its root to import mineral nutrient from environment. Both inorganic nitrogen source and plant hormone auxin influence the root system architecture (RSA). Previous study indicated that polar auxin transport is partly involved in ammonium-inhibition of primary root in an Arabidopsis ecotype, Columbia 0 (Col-0); however, the effect of auxin in other ecotypes remains unclear. The purpose of this study is to describe and examine the effect of TIBA, an inhibitor for the auxin polar transport, in ammonium supply-dependent changes of root development. Two Arabidopsis ecotypes, Col-0 and Landsberg erecta 2 (Ler-2), were used due to their different response to ammonium supply. The changes of the RSA in response to ammonium supply on vertical agar medium containing three levels of TIBA and four levels of ammonium were determined in two ecotypes. The primary root length of Ler-2 was markedly shortened by increasing ammonium concentration in the medium, while that of Col-0 was relatively insensitive to ammonium. Conversely, the lateral root length of Ler-2 was increased by ammonium supply. Both primary and lateral root of Col-0 were more sensitive to TIBA than those of Ler-2. ANOVA indicated the significant interaction of TIBA and ammonium in Col-0; however, no interaction in Ler-2. These results suggested the genetic diversity in the interactive effect of auxin and ammonium. [ABSTRACT FROM AUTHOR]