Current Issue : January - March Volume : 2016 Issue Number : 1 Articles : 6 Articles
This paper used ââ?¬Ë?ultrasonic lysis-cryptic growthââ?¬â?¢ in SBR to analyze the accumulation and chemical fraction distribution\nchanges of cadmium and lead in sludge. Results showed that ââ?¬Ë?ultrasonic lysis-cryptic growthââ?¬â?¢ technique cut sludge\nproduction by around 50%. Accumulation of cadmium and lead in sludge occurred in SBRs, and had light impacts on the\nperformance of bioreactors. The accumulation of cadmium was higher than that of lead. The co-existence of cadmium and\nlead in influent affected the accumulation of each other in sludge. Cadmium content in sludge first increased and decreased\nfinally. During 30-60 daysââ?¬â?¢ operation, the cadmium content in sludge of ââ?¬Ë?ultrasonic lysis-cryptic growthââ?¬â?¢ system was 56\ntimes more than the initial content in the seed sludge. Lead content change in sludge during 90 daysââ?¬â?¢ operation was just\nopposite to that of cadmium. After 30-60 daysââ?¬â?¢ operation, the Lead content in sludge decreased by 40%, comparing with the\ncontent after the first 30 daysââ?¬â?¢ operation. Chemical fraction distributions of both heavy metals changed with different\noperational durations. The exchangeable fraction of cadmium increased during 90 daysââ?¬â?¢ operation in control system;\nhowever, the changes were irregular in ââ?¬Ë?ultrasonic lysis-cryptic growthââ?¬â?¢ system. Possible reason was that sonication changed\nthe binding sites of sludge for cadmium. The residual fraction of lead was the main form in sludge, and the chemical fraction\ndistributions changed insignificantly in both bioreactors during 90 daysââ?¬â?¢ operation. It might be that lead in influent formed\ninsoluble salt and precipitated in sludge....
The dynamic neural network based adaptive direct nonlinear model predictive control is designed to control an industrial\nmicrowave heating pickling cold-rolled titanium process. The identifier of the direct adaptive nonlinear model identification and\nthe controller of the adaptive nonlinear model predictive control are designed based on series-parallel dynamic neural network\ntraining by RLS algorithm with variable incremental factor, gain, and forgetting factor. These identifier and controller are used to\nconstitute intelligent controller for adjusting the temperature of microwave heating acid.The correctness of the controller structure,\nthe convergence, and feasibility of the control algorithms is tested by system simulation. For a given point tracking, model mismatch\nsimulation results show that the controller can be implemented on the system to track and overcome the mismatch system model.\nThe control model can be achieved to track on pickling solution concentration and temperature of a given reference and overcome\nthe disturbance....
There is a growing concern over elevated CO2 levels and increased metal contamination in soils. Elevated atmospheric CO2\nusually increases plant productivity and alters nutrient elements mobility. However, it is still not clear whether rising CO2\ncan result in changes in contaminating elements in crops, for example in different rice cultivars. Therefore, in this study, a\npot experiment was conducted to investigate the combined effects of CO2 elevation levels and metals (Cu and Cd) on rice\ngrowth. The study showed that elevated CO2 led to higher tiller number, root length and grain yield when compared to\nambient CO2. Average Cu concentrations in the tissues of four rice cultivars with elevated CO2 levels were significantly\nlower than those with ambient CO2. The Cd concentrations in three parts of rice cultivars subjected to elevated CO2 levels\nwere higher than those in plants subjected to ambient CO2 levels. In addition, CO2 elevation significantly reduced the pH\nvalues of soils and changed the fractionation of Cu and Cd in soils. The associated risk was assessed using the hazard\nquotient (HQ), which was found to be high for Cd and Cu in all tested varieties of rice, with Cd posing a more severe threat\nthan Cu....
In this study activated carbon derived from oil-palm empty fruit bunch has been used as adsorbent for the removal of phenol,\nbutanol, butan-2-ol and 2-methyl butan-2-ol, as organic contaminants from stock solution. The effect of adsorbent dosage on\nadsorption operation was carried out in order to determine the optimal adsorption condition. The experimental data were analyzed\nusing four-parameter isotherm models (Fritz-Schluender and Baudu). However, all the parameters contained in those models,\ncorrelation coefficient (R2) and average percentage error (APE) were determined. The regression analysis result obtained proven\nthat equilibrium data for phenol and butan-2-ol fitted very well by the Baudu model while those of butanol and 2-methyl butan-2-ol\nwere well fitted by the Fritz-Schluender model....
The manganese complex of methionine hydroxy analogue was synthesized with methionine hydroxy analogue and manganese\nchloride as main raw materials. The composition and structure of the complex were characterized by elemental analyses, infrared\nspectra, and X-ray powder diffraction. The formula of the complex was Mn(C5H9O3S)2. The experimental results indicated that\nthe manganese ion was, respectively, coordinated by the carboxylic and hydroxyl oxygen atoms from the methionine hydroxy\nanalogue ligand.The crystal structure of the complex belonged to monoclinic system with the lattice parameters of a = 1.2775 nm, b =\n1.5764 nm, c = 1.5764 nm, and ...
The sorption of zinc ions from an aqueous solution using rice husk, a surplus agricultural by-product has been investigated. Some\nsimple and low-cost chemical modifications has resulted as an increase in the sorption capacity of raw rice husk. In particular,\nboiled rice husk has shown to be a very promising Zn2+ adsorbent as it is able to reduce metal concentrations and respect the\nlimits of law (0.5-1 mg/L). The effect of pH has also been evaluated, and it has resulted that the adsorption of metal ions\nincreases with an increase in the initial pH. The candidate adsorbent and work conditions have been determined in order to study\nand to design a fixed bed column system for industrial wastewater....
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