Study on optimal adsorption conditions of norfloxacin in water based on response surface methodology

The waste pomelo peel was pyrolyzed at 400 °C to prepare biochar and used as adsorbent to remove norfloxacin (NOR) from simulated wastewater. The adsorption conditions of norfloxacin by biochar were optimized by response surface methodology (RSM). On the basis of single-factor experiment, the adsorption conditions of biochar dosage, solution pH and reaction temperature were optimized by Box-Behnken Design (BBD), and the quadratic polynomial regression model of response value Y1 (NOR removal efficiency) and Y2 (NOR adsorption capacity) were obtained respectively. The results show that the two models are reasonable and reliable. The influence of single factor was as follows: solution pH > biochar dosage > reaction temperature. The interaction between biochar dosage and solution pH was very significant. The optimal adsorption conditions after optimization were as follows: biochar dosage = 0.5 g/L, solution pH = 3, and reaction temperature = 45 °C. The Y1 and Y2 obtained in the verification experiment were 75.68% and 3.0272 mg/g, respectively, which were only 2.38% and 0.0242 mg/g different from the theoretical predicted values of the model. Therefore, the theoretical model constructed by response surface methodology can be used to optimize the adsorption conditions of norfloxacin in water.

Preparation and Characterization of Starch Active Interface Calcium Carbonate for Biodegration

Calcium carbonate is so hard to be further developed in polymer applications because it is difficult to combine with other materials. Starch-coated calcium carbonate was prepared by using starch as the main modifier and sodium stearate and sodium hexametaphosphate as the auxiliary modifiers. Optimal modification conditions were tested by single factor experiment and orthogonal experiment optimization. Manifestation was evaluated with the help of Fourier infrared spectrometer (FT-IR) and laser particle size analyzer and other test instruments. Results showed that a starch film was successfully coated on the surface of calcium carbonate, and the edges and corners of the modified coated calcium carbonate were passivated, and the particles were rounded. The active interface calcium carbonate has a broad application prospect in the field of degradable biomaterials.

The Objective Conditions Study and Optimization of Digital Imaging System on Color Measurement：Case with Jadeite

The application of digital imaging to color measurement is more and more extensive, which also provides new ideas for gemology. In this paper, the single-factor experiment method and orthogonal experiment design are used to study the influence parameters of the digital imaging system (DIS) on gem color measurement. Among them, the illuminance has the most significant impact on the measurement results, followed by the exposure time, and the change of the measurement distance has an insignificant impact on the results; through range analysis and analysis of variance, the most suitable measurement parameters for red jadeite are 1600lx, 12500ms, 25cm.

Experimental evidence for recovery of mercury-contaminated fish populations

Anthropogenic releases of mercury (Hg)1–3 are a human health issue4 because the potent toxicant methylmercury (MeHg), formed primarily by microbial methylation of inorganic Hg in aquatic ecosystems, bioaccumulates to high concentrations in fish consumed by humans5,6. Predicting the efficacy of Hg pollution controls on fish MeHg concentrations is complex because many factors influence the production and bioaccumulation of MeHg7–9. Here we conducted a 15-year whole-ecosystem, single-factor experiment to determine the magnitude and timing of reductions in fish MeHg concentrations following reductions in Hg additions to a boreal lake and its watershed. During the seven-year addition phase, we applied enriched Hg isotopes to increase local Hg wet deposition rates fivefold. The Hg isotopes became increasingly incorporated into the food web as MeHg, predominantly from additions to the lake because most of those in the watershed remained there. Thereafter, isotopic additions were stopped, resulting in an approximately 100% reduction in Hg loading to the lake. The concentration of labelled MeHg quickly decreased by up to 91% in lower trophic level organisms, initiating rapid decreases of 38–76% of MeHg concentration in large-bodied fish populations in eight years. Although Hg loading from watersheds may not decline in step with lowering deposition rates, this experiment clearly demonstrates that any reduction in Hg loadings to lakes, whether from direct deposition or runoff, will have immediate benefits to fish consumers.

Antimicrobial evaluation and paper protection of cellulose-traditional Chinese medicine A

As the main carrier of cultural inheritance, paper cultural relics are easily affected by the microorganism and external environment. In order to protect paper cultural relics, in this paper, traditional Chinese medicine A and sodium carboxymethyl cellulose (CMC) were prepared into a multi-functional mixture solution to use for antibacterial and reinforcement of paper relics. The antibacterial effects of the A on Escherichia coli and Staphylococcus aureus were studied through the single factor experiment. The minimum inhibitory concentration (MIC) of A and the concentration range of A-CMC for paper reformulation were determined. The results showed that the MIC values of A to Escherichia coli and Staphylococcus aureus were 0.2 mg/ml. The optimal ratio of the composite liquid is 0.8% CMC concentration and 0.2 mg/ml A. Under this condition, the paper has a good bacteriostatic effect. This showed that the traditional Chinese medicine A can be used as an antibacterial agent for paper. Keywords: Traditional Chinese Medicine A, bacteriostasis, CMC, paper properties.

Soil Chemical Properties and Maize (Zea mays L.) Yield influenced by Lime and Fern (Pteris vittata)

This study aimed to investigate the influence of liming and fern on reducing the absorption of arsenic (As) by maize and As content in the soil. The single-factor experiment was designed in a completely random block (4 treatments and 4 replicates). Treatments were followed: Treatment 1 (NT1) liming (3tons CaO.ha-1); NT2: Plant ferns alternately with maize (without liming); NT3: Plant ferns alternately with maize and liming (3 tons CaO.ha-1); NT4: Control (no liming or ferns). The results showed that the applications of liming and ferns have positive influences on the soil pH, EC, OM, yield, and yield components of the maize tested in this study. The yield difference between the application of liming and intercropped ferns was increased from 5.4 to 22.3 %. Moreover, the arsenic contents in soil, stems, and seeds were 25.7, 32.0 and 50 % lower than that of the control, respectively. soil to roots and stems, which significantly caused reduction of a large amount of As content in soils. Therefore, to reduce the production cost, and enhance soil and maize quality, application of lime (3 ton.ha-1) and intercropped ferns is recommended. HIGHLIGHTS Increasing pH, EC and organic matter by the lime application combined with ferns Decreasing the soil arsenic concentration by intercroping maizes and ferns The lime application combined with ferns raising the yield components and yield of maize The high As accumulation of stems and shoots of ferns intercroping maizes and ferns The lowest As accumulation of stems and seeds of maizes applying the lime combined with ferns

Preparation and Performance of Structure Controllable Biochar Obtained From Cattail-Sludge Composites

Biochar obtained from cattail-sludge composites (BC/CS) was treated as a raw material, with monopotassium phosphate and ammonium chloride solution as absorbents, to find the best parameters for the preparation of structure controllable biochar (BC/SC). Slow pyrolysis and single factor experiment method were employed in the preparation of BC/CS and BC/SC, with EA, BET and SEM to illustrate the performance of BC/SC. The results showed that the best parameters for BC/CS were characterized by a ratio of cattail-sludge composites (60:40, wt%), a charring temperature of 500℃, a charring time of 0.5 hrs, KOH as an activator, an immersion ratio of 4 mL·g-1, an activation concentration of 300 g·L-1 and an immersion time of 6 hrs; the best parameters for BC/SC contained a sizing amount of 60%, a molding pressure, temperature and time of 5 N (cm2)-1, 160℃, and 95 min, respectively; compared to BC/CS, BC/SC was characterized by a higher content of H but a lower O content, leading to the increase in its hydrophobicity and stability; in addition, the addition of polyethylene enabled an increase in the pore diameter of BC/SC and a close bond with particles on the surface. Meanwhile, in BC/SC, the surface functional groups of CH3 and C—O—C were reduced in their contents, in contrast to a large amount of C crystals on its surface. Such results could provide a new process for resource recycling of cattail and sludge, as well as evidence for material selection in the treatment of eutrophication water bodies.

Preservative solutions on vase life and quality of cut Polianthes tuberosa L.

ABSTRACT This experiment was conducted to study the effectiveness of different preservative solutions on vase life and quality of angelica cut inflorescences cv. Single. The concentrations of citric acid at 100, 200 and 300 mg L-1, sucrose at 3% and 4% and H2O2 at 0.1%, 0.2% and 0.3% were used as preservatives, while distilled water was used as control. The single factor experiment was laid out in a completely randomized design (CRD) with three replications. Citric acid and H2O2 solutions effectively inhibited bacterial growth-related blockage in the vascular tissues, but had adverse effects on the vase life. The inflorescences stored in sucrose (3% and 4%) solutions remained fresh up to 10 days after preservation (DAP), maintaining good solution uptake, controlling transpiration loss and gaining higher relative fresh weight. Different quality parameters like floret diameter and number of opened florets were also significantly higher in inflorescences preserved in sucrose (3% and 4%) solution, followed by control, citric acid and H2O2, respectively, in different DAP. Overall, the inflorescence of cut tuberose preserved in sucrose, particularly at 4% solutions, showed better postharvest quality than other preservatives and maximum vase life.

DESIGN AND TEST OF AIR-SUCTION PEPPER SEED METERING DEVICE BASED ON AIR SUPPLY AND QUANTITATIVE SEED SUPPLY

In order to solve the problem that the current precision seeder has difficulty in precision sowing pepper seeds, an air-suction pepper seed metering device based on air supply and quantitative seed supply was developed. Combined with its basic structure and working principle, the CFD-DEM coupling method was used for analysis, and the best combined hole parameters were obtained. A single factor experiment with the pass rate, replay rate, and missed rate as experimental indicators was designed. Regression model was established to obtain a reasonable range of each parameter. The results showed that when the speed of the drum barrel was 28.65r/min and the working negative pressure was 4.40kPa, the seeding pass rate of the seed meter was 91.32%, the replay rate was 4.51%, and the missed rate was 4.17%. The comprehensive performance index was better.

Experimental Evaluation of Rootstock Clamping Device for Inclined Inserted Grafting of Melons

A grafting machine is a kind of machine that can quickly graft scion to rootstock instead of manual grafting. Currently, an inclined inserted grafting machine uses the mechanical clamping method, which can easily damage the rootstock seedlings due to its high stiffness, thus, reducing the success rate of grafting. This study proposed an effective, flexible clamping device for grafting. The suction hole diameter (HD), the negative pressure (NP), and the surface inclination angle (IA) of the clamping device were studied via a single factor experiment to obtain optimal parameter ranges. Optimal HD, NP, and IA were 2–3 mm, 4–8 kPa, and 10–20°, respectively. The orthogonal experiment results showed that the optimal parameter combination for maximum holding success rate was HD, 2.5 mm; NP, 6 kPa; and IA, 10°. The experimental verification was carried out using the optimal parameter combination, with a holding success rate of 98.3% and no damage. This study provides a reference for the optimal design of an inclined inserted grafting machine.