Robert Lian-Huey Liu

Textile Wastewater Treatment With Activated Sludge And Powdered Activated Carbon

The objective of the study is to determine the effectiveness of batch activated sludge process and powdered activated carbon adsorption for organic and color removal from textile wastewaters. Factors affecting treatment performance investigated in the study included raw wastewater strength, various combinations of dye to starch in the wastewater, aeration time. Synthetic wastewaters using starch solution and disperse-red-60 dye were used in the adsorption study. The 3 wastewater strengths used included low, medium and high strength. The 5 different dye to starch combinations used included 0% dye+100% starch, 25% dye+75% starch, 50% dye+50% starch, 75% dye+25% starch, and 100% dye+0% starch. The batch bio-oxidation was conducted for a period of 24 hours. The COD removal efficiency, color removal, bio-oxidation rate constant, F/M ratio, SVI, pH and temperature were determined. The results indicated that starch was much easier to remove by the batch activated sludge process compared to disperse-red-60 dye, which was virtually non-biodegradable. Wastewaters containing 100% starch had the highest COD removal efficiency. Increase in dye concentration in wastewater resulted in decrease in the COD removal efficiency. The COD removal efficiency ranged from 6 to 45% for low strength wastewater of 100mg/L COD, 27 to 80% for medium strength wastewater of 500mg/L COD, and 23 to 65% for high strength wastewater of 1000mg/L COD. The low strength wastewaters had the best settling characteristics, while the medium strength wastewaters had the worst. For high PAC dosage of 15g/L, high COD removal efficiencies of 88 to 98% removal and E * ab of 36 to 47 were obtained. It is recommended that activated sludge be used to remove high COD organic pollutants first, followed by PAC adsorption to remove dye waste in the treatment of textile wastewaters.

Comparative study of adsorption capacity of various adsorbents for treating dye wastewaters

The objective of this laboratory study was to determine the effect of dosage, contact time and type of adsorbents on the color and COD (chemical oxygen demand) removal for dye wastewaters. The adsorption parameters for Langmuir and Freundlich isotherms and mass transfer coefficients from bulk solution to particle surfaces for disperse dye were also determined. The adsorbents used in this study included powdered activated carbon (PAC), granular activated carbon (GAC), activated alumina, molecular sieves, diatomite, and sawdust. For an initial dye concentration of 150 ppm and adsorbent dosage of 15 g/1 and a contact time of 2 hours, the COD removal efficiency was 98%, 60–65%, and 24–30%, for PAC, activated alumina, and molecular sieves, respectively. The order of adsorbent efficiency was found to be: PAC > activated alumina > molecular sieves > GAC > diatomite. The adsorption capacity of diatomite and GAC was very poor. The color removal (color difference or AE∗ab) varied from 45 to 55 for most adsorbents s...

The general utilization of scrapped PC board

The traditional burning process is used to recover copper from scrapped PC board (printed circuit board) but it causes serious environmental problems. In this research a new process was developed which not only prevents pollution problems, but also maximizes the utility of all the materials on the waste board. First, the scrapped PC board was crushed and grounded, then placed in the NH3/NH5CO3 solution with aeration in order to dissolve copper. After distilling the copper NH3/NH5CO3 solution and then heating the distilled residue of copper carbonate, pure copper oxide was obtained with particle size of about 0.2 microm and the shape elliptical. The remaining solid residue after copper removal was then leached with 6N hydrochloric acid to remove tin and lead. The last residue was used as a filler in PVC plastics. The PVC plastics with PC board powder as filling material was found to have the same tensile strength as unfilled plastics, but had higher elastic modulus, higher abrasion resistance, and was cheaper.

Synthesis and Bactericidal Ability of TiO2 and Ag-TiO2 Prepared by Coprecipitation Method

Preparation of photocatalysts of TiO2 and Ag-TiO2 was carried out by coprecipitation method. The prepared photocatalysts were characterized by X-ray diffraction (XRD), SEM, EDX, and XRF analysis. The disinfection of E. coli, a model indicator organism for the safe water supply, was investigated by using TiO2 and Ag-TiO2 under different light sources. The treatment efficacy for the inactivation of E. coli would be UV/Ag-TiO2; visible/Ag-TiO2; dark/Ag-TiO2; UV (all 100%) > UV/TiO2 (99%) > visible/TiO2 (96%) > dark/TiO2 (87%) > visible (23%) > dark (19%). The order of disinfection efficiency by their corresponding kinetic initial apparent rate constants, 𝑘app, (min−1) would be UV/Ag-TiO2; visible/Ag-TiO2 (both 6.67) > UV (6.6) > dark/Ag-TiO2 (6.56) > UV/TiO2 (1.62) > visible/TiO2 (1.08) > dark/TiO2 (0.7) > visible (0.28) > dark (0.03). The application of TiO2 doped with silver strongly improved the ability of disinfection treatment. The study of mineralization of E. coli by measurement of TOC (total organic carbon) removal percentage showed that the visible light may effectively be applied for the disinfection unit of water and wastewater treatment system by using photocatalysts of Ag-TiO2.

Oxidation pond for municipal wastewater treatment

This literature review examines process, design, and cost issues related to using oxidation ponds for wastewater treatment. Many of the topics have applications at either full scale or in isolation for laboratory analysis. Oxidation ponds have many advantages. The oxidation pond treatment process is natural, because it uses microorganisms such as bacteria and algae. This makes the method of treatment cost-effective in terms of its construction, maintenance, and energy requirements. Oxidation ponds are also productive, because it generates effluent that can be used for other applications. Finally, oxidation ponds can be considered a sustainable method for treatment of wastewater.

Colloid Interaction and Coagulation of Dye Wastewater with Extra Application of Magnetites

The feasibility of treating direct dye wastewater by coagulation is investigated herein. The theoretical development of colloid interactions for coagulation is also reviewed. Ferric chloride and its combination with hydrated lime [Ca(OH) 2 ] is used as a coagulant. Treatment for high strength dye wastewater is preferred and better than medium strength wastewater which showed slow settling velocity and long settling time. The effect of magnetic powder on ferric chloride coagulation system reveals an obvious improvement in settling, particularly for medium strength direct dye wastewater. In addition, increasing magnetite (Fe 3 O 4 ) dosages enhances the treatment efficiency of settling.

Adsorption Study of Dye Wastewater with Powdered Activated Carbon

A study to determine the effectiveness of PAC on the removal of COD and colour from dye wastewater. Factors affecting treatment efficiency were investigated and included PAC particle sizes, initial dye concentration and contact time. The adsorption parameters for Langmuir, Freundlich and Dziubek′s isotherms were determined. Results indicated that a very short contact time of one hour was needed to reach equilibrium of adsorption. A COD (chemical oxygen demand) removal efficiency of 90 per cent for disperse‐red‐60 dye wastewater was obtained with PAC (powdered activated carbon). With PAC dosage of less than 15g/l the adsorption followed both Freundlich′s and Langmuir′s isotherms. The ultimate capacity of the adsorption increased with decreasing PAC particle sizes or the initial dye concentration. The mass transfer coefficient was determined in this study.

Degradation of FBL dye wastewater by magnetic photocatalysts from scraps

Magnetic photocatalyst solves the separation problem between wastewater and TiO2 photocatalysts by the application of magnetic field. This research investigates the treatment of simulated FBL dye wastewater using Mn-Zn ferrite/TiO2 magnetic photocatalyst. The magnetic Mn-Zn ferrite powder was first produced by a chemical coprecipitation method from spent dry batteries and spent pickling acid solutions. These two scraps comprise the only constituents of Mn-Zn ferrite. The as-synthesized Mn-Zn ferrite was then suspended in a solution containing Ti(SO4)2 and urea. Subsequently a magnetic photocatalyst was obtained from the solution by chemical coprecipitation. The prepared Mn-Zn ferrite powder and magnetic photocatalyst (Mn-Zn ferrite/TiO2) were characterized using XRD, EDX, SEM, SQUID, BET, and so forth. The photocatalytic activity of the synthesized magnetic photocatalysts was tested using degradation of FBL dye wastewater. The adsorption and degradation studies by the TOC and ADMI measurement were carried out, respectively. The adsorption isotherm and Langmuir-Hinshelwood kinetic model for the prepared magnetic TiO2 were proved to be applicable for the treatment. This research transforms waste into a valuable magnetic photocatalyst.

Synthesis and Application of Magnetic Photocatalyst of Ni-Zn Ferrite/TiO2 from IC Lead Frame Scraps

IC lead frame scraps with about 18.01% tin, 34.33% nickel, and 47.66% iron in composition are industrial wastes of IC lead frame production. The amount of thousand tons of frame scraps in Taiwan each year is treated as scrap irons. Ni-Zn ferrites used in high frequent inductors and filters are produced from Ni-Zn ferrite powders by pressing and sintering. The amount of several ten thousand tons of ferrites of in compositions is consumed annually in the whole world. Therefore, these IC lead frame scraps will be used in this research as raw materials to fabricate magnetic ferrite powders and combined subsequently with titanium sulfate and urea to produce magnetic photocatalysts by coprecipitation for effective waste utilization. The prepared Ni-Zn ferrite powder and magnetic photocatalyst (Ni-Zn ferrite/TiO2) were characterized by ICP, XRF, XRD, EDX, SEM, SQUID, and BET. The photocatalytic activity of synthesized magnetic photocatalysts was tested by FBL dye wastewater degradation. TOC and ADMI measurement for degradation studies were carried out, respectively. Langmuir-Hinshelwood kinetic model of the prepared magnetic TiO2 proved available for the treatments. Wastes are transformed to valuable magnetic photocatalysts in this research to solve the separation problem of wastewater and TiO2 photocatalysts by magnetic field.

Effect of the Doping Ni and Overdosing Lithium for Synthesis LiMn2O4 Cathode Material by the Solid State Reaction Method

The study with Li2CO3 and Mn3O4 through the solid state reaction makes cathode material for lithium battery spinel - LiMn2O4. According to past literature, under the solid-state reaction. The experiment carries out sintering at temperature of 850°C.. Cathode materials under these sintering temperatures are made to fabricate battery. For Ni doped LiMn2O4, the capacitance decreasing speed is slow and stable; after 15 times charging-discharging cycles, the attrition rates were 3.05 % or less. The result of experiment demonstrates that the best sintering temperature is at 850°C. Under the condition of 850°C, various contents for extra amount of lithium (1.02 mole-1.1 mole) are fabricated and range of working voltage is released. It is found a further increase of initial capacity to 140.51 mAh/g. LiMn2O4 further extends circulation and usage.