Combination of photocatalytic degradation and adsorption in dye removal by TiO2-chitosan-glycerol beads under natural sunlight

The synthesis of TiO2-chitosan-glycerol (TiCsG) beads was prepared to determine the optimum condition for dye removal under natural sunlight. By using the orthogonal array design with five parameters (ratio of TiO2/Chitosan, initial concentration of dyes, pH of solution, irradiation time, dose of TiCsG) to analyze their interaction such as well as optimizing the photocatalytic process. The significant parameters influent in the removal of Acid Blue 193, MO, NWY dyes were irradiation time (p = 0.011) and the ratio of TiO2/chitosan (p = 0.025), while the initial concentration of dyes, pH of dye solution and dose of TiCsG were unimportant factors with p > 0.05. The optimum of factors based on the ratio of signal per noise to attain the highest dye removal ability of TiCsG was the percentage of TiO2/chitosan = 2 % w/w (level 2), initial concentration of dye at level 5 (10 mg/L of AB 193, 5 mg/L for MO and 100 mg/L for NWY), pH =4.5 (level 2), irradiation time =1.5 h (level 5) and dose of TiCsG =0.2 g/mL (level 4).

Hydrometallurgical Recycling of Copper Anode Furnace Dust for a Complete Recovery of Metal Values

Copper anode furnace dust is waste by-product of secondary copper production containing zinc, lead, copper, tin, iron and many other elements. Hydrometallurgical Copper Anode Furnace dust recycling method was studied theoretically by thermodynamic calculations and the proposed method was verified experimentally on a laboratory scale. The optimum condition for leaching of zinc from dust was identified to be an ambient leaching temperature, a liquid/solid ratio of 10 and H2SO4 concentration of 1 mol/L. A maximum of 98.85% of zinc was leached under the optimum experimental conditions. In the leaching step, 99.7% of lead in the form of insoluble PbSO4 was separated from the other leached metals. Solution refining was done by combination of pH adjustment and zinc powder cementation. Tin was precipitated from solution by pH adjustment to 3. Iron was precipitated out of solution after pH adjustment to 4 with efficiency 98.54%. Copper was selectively cemented out of solution (99.96%) by zinc powder. Zinc was precipitated out of solution by addition of Na2CO3 with efficiency of 97.31%. ZnO as final product was obtained by calcination of zinc carbonates.

The Effect of Ball Milling Time on the Isolation of Lignin in the Cell Wall of Different Biomass

Ball milling technology is the classical technology to isolate representative lignin in the cell wall of biomass for further investigation. In this work, different ball milling times were carried out on hardwood (poplar sawdust), softwood (larch sawdust), and gramineous material (bamboo residues) to understand the optimum condition to isolate the representative milled wood lignin (MWL) in these different biomass species. Results showed that prolonging ball milling time from 3 to 7 h obviously increased the isolation yields of MWL in bamboo residues (from 39.2% to 53.9%) and poplar sawdust (from 15.5% to 35.6%), while only a slight increase was found for the MWL yield of larch sawdust (from 23.4% to 25.8%). Importantly, the lignin substructure of ß-O-4 in the MWL samples from different biomasses can be a little degraded with the increasing ball milling time, resulting in the prepared MWL with lower molecular weight and higher content of hydroxyl groups. Based on the isolation yield and structure features, milling time with 3 and 7 h were sufficient to isolate the representative lignin (with yield over 30%) in the cell wall of bamboo residues and poplar sawdust, respectively, while more than 7 h should be carried out to isolate the representative lignin in larch sawdust.

Modelling of Jatropha Oil Hydrocracking in a Trickle-Bed Reactor to Produce Green Fuel

Trickle-bed reactor (TBR) modelling to produce green fuel via hydrocracking of jatropha oil using silica-alumina-supported Ni-W catalysts was performed in this research. The objectives of this study are to obtain a TBR with good heat transfer and the optimum condition for high purities of products. A two-dimensional axisymmetric model with a diameter of 0.1 m and a length of 10 m was used as a representative of the actual TBR system. Heterogeneous phenomenological models were developed considering mass, energy, and momentum transfers. The optimisation was conducted to obtain the highest green fuel purity by varying catalyst particle diameter, inlet gas velocity, feed molar ratio, and inlet temperature. The simulation shows that a TBR with an aspect ratio of 100 has achieved a good heat transfer. The diesel purity reaches 44.22% at 420°C, kerosene purity reaches 21.39% at 500°C, and naphtha purity reaches 25.30% at 500°C. The optimum condition is reached at the catalyst diameter of 1 mm, the inlet gas velocity of 1 cm/s, the feed molar ratio of 105.5, and the inlet temperature at 500°C with the green fuel purity of 69.4%.

Optimization Study of Adsorption Parameter for Removal of Dye Pollutant Using Candle Soot Coated Egg Carton

In this study, several parameters that affect the adsorption capacity of Rhodamine B (RhB) dyes were reviewed which include initial pH, temperature, contact time and initial dye concentration. Experimental data was extracted from other literatures as input for subsequent optimization study. Design Expert version 11.1.2.0 software was used to find the optimal condition for adsorption of RhB dyes from wastewater by using candle soot coated on egg carton (CS-Egg) as absorbent. The Central Composite Design (CCD) in response surface methodology (RSM) was employed to perform the optimization and analysis process as it was effective in determining the optimal condition for the adsorption process. CCD evaluated many parameters at the same time and thus reducing the number of experiments required. The optimum condition to maximize the adsorption efficiency was obtained at pH 7, 262.5 mg/L, 60 min of contact time and 55 °C. The highest predicted adsorption efficiency of RhB dye was 90 % at optimum condition. The optimization of parameter provides a better understanding on the adsorption efficiency before conducting the actual experimental work.

Evaluation of Strength and Microstructural Properties of Heat Treated High-Molybdenum Content Maraging Steel

Effect of high molybdenum content ~10% as an alloying element on the strength and microstructural properties of 11% nickel—1.25% titanium maraging steel was evaluated. To increase the homogeneity and cleanliness of produced ingot, the investigated steel sample was produced by melting the raw material in an open-air induction melting furnace followed by refining utilizing a direct current electro-slag refining machine. The produced steel samples were both forged and heat-treated in optimum condition to acquire the full capacity of mechanical properties especially the tensile properties. After Forging and heat treatment at optimum condition, steel samples were evaluated by optical microscopy (OM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) analysis, electron backscattering diffraction (EBSD), and transmission electron microscopy (TEM). The experimental data showed that this steel sample has ultimate strength ~2100 MPa and elongation around 14%. High tensile properties obtained may be attributed on one hand due to the presence of high alloying lamellar martensite phase and lamellar austenite phase which has high dislocation intensity, and on the other hand, due to the high homogeneity and cleanliness of investigated samples from large nonmetallic inclusions. The results also show that a high amount of intermetallic compounds (NiMo3 and NiTi3) which are completely round and have a very low size not more than hundred nanometers.

The Utilization of Lapindo Mud Waste for Aluminium Sulfate Production

The Lapindo mudflow disaster in East Java Province, or also known as LUSI (LUmpur “mud”-SIdoarjo) has become spectacular longest ongoing disaster in recent memory since 2006. The utilization of volcanic Lapindo mud could be the promising solution to prevent further environmental damage. The chemical composition of Lapindo mud contained of 44.1% SiO2, 23.7% Fe2O3, 13% Al2O3, 7.02% CaO, 5.35% MoO3, 2.53% K2O, 1.84% TiO2 and 0.7% Na2O. Aluminium sulfate (Al2(SO4)3) or “alum” have been widely used as coagulation compound in water treatment, paper and textiles industry. Aluminium sulfate can be synthesized from aluminium oxide (Al2O3) from Lapindo mud with acidic solutions (H2SO4). The aim of this work was to synthesize aluminum sulfate from Lapindo mud by using extraction process. The impact of H2SO4 concentration and heating time to the production of aluminium sulfate have been investigated. The results showed that the aluminium sulfate can be synthesized from Lapindo mud by using H2SO4. Based on XRF analysis, the variation of heating time and H2SO4 concentration affect the aluminium sulfate conversion. The increasing of heating time and H2SO4 concentration directly enhance the conversion until reach the optimum condition. The optimum condition for aluminium sulfate synthesis from Lapindo mud (75.78% conversion) was found to be 90 min for heating time with H2SO4 concentration of 80%

Efficient Removal of 2,4-DCP by Nano Zero-Valent Iron-Reduced Graphene Oxide: Statistical Modeling and Process Optimization Using RSM-BBD Approach

In this study, nano zero-valent iron-reduced graphene oxide (NZVI-rGO) composites were synthesized to remove 2,4-dichlorophenol (2,4-DCP) as an efficient adsorbent. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) indicated that NZVI particles were successfully loaded and dispersed uniformly on rGO nanosheets. Fourier transform infrared spectroscopy (FTIR) analysis showed that the interaction between NZVI-rGO and 2,4-DCP promoted the adsorption process. A three-level, four-factor Box-Behnken design (BBD) of the response surface methodology (RSM) was used to optimize the influencing factors including NZVI-rGO dosage, 2,4-DCP initial concentration, reaction time and initial pH. A statistically significant, well-fitting quadratic regression model was successfully constructed to predict 2,4-DCP removal rate. The high F value (15.95), very low P value (<0.0001), nonsignificant lack of fit, and appropriate coefficient of determination ( R 2 = 0.941 ) demonstrate a good correlation between the experimental and predicted values of the proposed model. The analyses of variance reveal that NZVI-rGO dosage and reaction time have a positive effect on 2,4-DCP removal, whereas the increase of contaminant concentration and initial pH inhibit the removal, whereas the effect of contaminant concentration and initial pH is in reverse, where the change of NZVI-rGO dosage has the greatest effect. The optimum condition is1.215 g/L of NZVI-rGO dosage, 20.856 mg/L of 2,4-DCP concentration, 4.115 of pH, and 8.157 min of reaction time. It is verified by parallel experiments under the optimum condition, achieving the removal efficiency of100%.

Produksi Enzim Fibrinolitik Tempe oleh Rhizopus oryzae FNCC 6078

ackground Rhizopus oryzae FNCC 6078 had been evaluated producing fibrinolytic enzyme under solid state fermentation. Soybean had been used to produce fibrinolytic enzyme through fermentation in tempeh. The main purpose of this study was to reveal optimum condition for fermentation. The parameters of the condition were inoculum volume, incubation period and temperature. Optimum condition was defined by maximum fibrinolytic activity. Methode Fibrinolytic activity was measured using spectrophotometry at 274 nm. Result optimum condition for producing fibrinolytic enzyme was 1,5 mL volume of inoculum of Rhizopus oryzae suspension in 25%T, 42 hours for incubation period and 35oC temperature incubation.