Papers by Keyword: Pre-Treatment

Abstract: The ability of an iron-sulfur-oxidizing mixotrophic bacterium to treat two types of sulfide-rich carbonaceous refractory gold concentrates from Sulawesi and Sumatra in Indonesia was studied in comparison with an acidophilic chemolithotrophic bacterium Acidithiobacillus ferrooxidans. Over the course of the biooxidation experiments, the pH of the solution tended to rise (pH>5) due to the high content of acid-consuming minerals such as carbonates in both concentrates. Ferric ions were frequently observed to precipitate due to high solution pH. The BIOX^skc employed in this study was able to increase the gold extraction from low sulfidic carbonaceous refractory gold concentrates by ~15% higher than that by using At. ferrooxidans. It was also capable of treating carbonaceous matters which causes preg-robbing effect and retaining iron in ionic form due presumably to the production of extracellular polymeric substances (EPS) under high solution pH. Nevertheless, BIOX^skc also reduced the gold extraction yield of high sulfidic gold concentrates because of passivation effect. It is suggested that the precipitation of iron and sulfur on the surface of sulfide minerals during biooxidation may prevent cyanide ion contact with gold.

Abstract: Black tilapia (Oreochromis mossambicus) fish scales are good sources of gelatin. Fish scales needs to undergo adequate demineralization (pre-treatment) process in order to be a suitable medium for gelatin extraction. The effect of hydrochloric acid (HCl) concentrations (1-5 %) and pre-treatment time (4-20 h) on the raw tilapia scales have been determined. Scanning Electron Microscopy (SEM) analysis was done on the raw scales before and after pre-treatment process. SEM images reveal the pattern of ridges on the scales that fades away at different treatment conditions. Energy Dispersive X-ray Spectroscopy (EDX) results indicate that 3% of HCl with 12 h of treatment time is adequate for demineralization of the fish scales. These were further proved by Fourier Transform Infrared Spectroscopy (FTIR) analysis, where no any inorganic components been detected in the pre-treated scales in comparison to raw scales.

Abstract: In this paper, for the re-concentration of sliming molybdenum Tailings in Henan Province, a multi-parameter test is carried out using orthogonal method in the column flotation system with the ultrasonic pre-treatment. Two groups’ optimum parameters of ultrasonic pre-treatment are acquired through the analysis of orthogonal test results. In addition,those two groups parameters are selected to verify the test results. Furthermore, the impact of ultrasonic pre-treatment on the floatability of mineral are defined by comparison tests. All the tests show that ultrasonic pre-treatment promotes the flotation of sliming molybdenum tailings..

Abstract: Theestablishment of Aquilariaspp in producingagarwoodisgaining more and more attentionlately, especially withgrowinginterest in agarwoodoilextraction. Thus, theoilextractionsomehow produces abundantwaste of processedagarwood.Theintent of thisresearchistoutilizewastefromagarwoodoilextractionprocess,wherethesilicacontentin thiswastewasdetermined.A preliminarystudywasconductedontheeffect of hydrochloricacidtreatments ofagarwoodwasteon FTIR profile. Aftersoakingovernightwithdifferentacidconcentration; 0.3M, 0.5M and 1M, allthesamplesweredried and analyzedbyusingfouriertransform infra red (FTIR). Theresult shows theexistence of silicagroup in thewaste at 1031 cm^-1peak. Thehighestsilicaintensityfoundwas86%,obtainedfromthesample of agarwoodwastetreatedwith 0.3M HCl.However, theintensitydecreasedproportionaltoincreasingacidconcentrationduetothedecrement of thesilicaconcentrationdetectedbytheinstrument.

Abstract: Combining the application of tea saponin in short pre-treatment of cotton fabric, the chemical reaction characteristics and mechanism of one-bath process were discussed. The impact of various parameters on the one bath process with tea saponin was analysed, and the optimum process prescription was obtained: tea saponin 40 g/L, penetrating agent JFC 5 g/L, scouring agent YS198 6 g /L and hydrogen peroxide stabilizing agent GJ-101 4 g/L. By tea saponin qualitative analysis, the action mechanism of tea saponin in one bath pretreatment was proposed.

Abstract: The influences of different annealing temperatures and pre-strains on the coupling effect between TiNi matrix and the Nb nanowire were studied by means of synchrotron X-ray diffraction in form of variation in lattice strain of the nanowire upon temperature changing for four groups of samples. For every annealing temperature, variation in Nb (110) lattice strains initially increasing with increasing pre-strain and then decreased after 12% pre-strain. A maximum variation in Nb (110) lattice strain was observed approaching 2.4% within the sample 450°C-20min annealed and 12% pre-strained. Such variations in lattice strain of the embedded nanowires upon temperature changing provided the composite great potentials as structural-functional integrated two-way actuators.

Abstract: The research on accelerated seeded precipitation pre-treatment for the improvement of secondary RO membrane was investigated. The influences of seed type, initial pH and seed dosage on accelerated seeded precipitation were studied. SEM images for the secondary RO membrane were also discussed.

Abstract: Metal supported catalysts in hydrogen production reactor has a very broad application prospect. However, the film adhesion of active coating with the metal support is the key problem which needed to be solved urgently. In this paper, FeCrAl alloy was chosen as the metallic substrate. The effects of oxidation temperature and time on the morphology, crystal phase and element composition of the metal surface were investigated by XRD, SEM and EDAX. The results show that after pre-treatment of FeCrAl Metallic Substrate,a dense transition layer of α-Al₂O₃ formed on the surface of the metallic support. Thus the oxidized α-Al₂O₃ layer and the γ-Al₂O₃ coating could combine together better. The optimum pre-treatment condition is at 950°C for 10h in air atmosphere.

Abstract: Ultra-Violet (UV) photocatalytic degradation and anaerobic digestion (AD) were applied in the treatment of methylene blue (MB) dye. South African natural zeolite was used as a catalyst support and biomass support in the photocatalysis and AD process respectively. It was found that UV photocatalysis pre-treatment of MB dye before the AD process improved its biodegradability. This resulted in higher biogas production coefficient compared to the non-UV pre-treated MB dye.

Abstract: A comparative study of three kinds of electrolysis methods: indirect electro-oxidation, electro-flocculation and electro-Fenton, as pre-treatment processes for a real dyestuff wastewater with high salinity and unbiodegradable organics were investigated. The efficiency of each method was evaluated according to the reduction levels of COD and toxicity, as well as biodegradability improvement. The results indicate electro-Fenton process as the most efficient pre-treatment method for improving biodegradability, reducing toxicity, and removing organic pollutants from dyestuff wastewater.