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A significant amount of electric arc furnace slag (EAFS) is generated as a by-product from the steelmaking industry. Acid leaching was carried out with both the presence and absence of oxidants to intensify the iron recovery from EAFS in the final product. Oxidative leaching refers to the process whereby the oxidant helps in removing one or more electrons in a chemical reaction. In contrast, non-oxidative leaching means there is no transfer of electrons during the process. In this study, hydrogen peroxide and potassium permanganate were used as the oxidants in the leaching process. The influences of the leaching factors, such as the concentration of leaching reagent (0.5–8 M), leaching temperature (323–363 K), EAFS particle size (50–300 μm) and concentration of the oxidants (0.5–2 M), were also studied. The findings revealed that the particle size, acid dosage and type of oxidants significantly influenced iron recovery. Smaller particle sizes greatly improved the recovery of iron. İn the non-oxidative leaching environment, sulphuric acid exhibited a higher iron recovery than hydrochloric acid. The recovery efficiency was 21.47% higher. For oxidative leaching, the leaching efficiency of iron was more favourable at lower concentrations of hydrogen peroxide in both sulphuric and hydrochloric acid, and the opposite was the case for potassium permanganate. An overdose of hydrogen peroxide can cause radical quenching, which will reduce oxidant utilisation. Oxidative leaching resulted in better iron recovery at optimum leaching conditions with a temperature of 50°C, 5 M H2SO4, 1 M hydrogen peroxide, a leaching time of 60 minutes, a solid to liquid ratio of 1:20 and a stirring rate of 300 rpm.

The steelmaking process produces a substantial amount of electric arc furnace slag (EAFS). Therefore, this present study conducted acid leaching, with and without the use of oxidants such as hydrogen peroxide (H2O2) and potassium permanganate (KMnO4), to increase the amount of iron (Fe) recovered from the EAFS. The effect that reagent concentration of 0.5-8.0 M, leaching temperatures of 50-90 °C, and oxidant concentrations of 0.1-2.0 M had on leaching activities were investigated. A temperature of 50 °C, a 5 M sulphuric acid (H2SO4) concentration, a 1 M hydrogen peroxide concentration, a leaching duration of 60 minutes, a 1:20 solid: liquid (S: L) ratio, and a 300-rpm stirring rate was found to yield the highest iron. recovery. Three kinetics models; diffusion-controlled, chemical reaction-controlled and mixed-controlled model; were also investigated. The reaction was found to follow the chemical-reaction model as it yielded the highest square of the correlation coefficient (R2, 0.9998). The activation energy of the chemical reaction-controlled model was +16.95 kJ/mol. During the cyclic voltammetry (CV) study, 0.1 M sodium chloride (NaCl) was added to the iron-rich leaching solution to act as a supporting electrolyte. Tests were then conducted at potential ranges of -1-1 V at a scan rate of 100 mV/s using screen printed carbon electrode (SPCE). The CV indicated that there were two distinct oxidation peaks (-1.5 and .5 V) and two distinct reduction (0.9 and -0.9 V) peaks occurred at all temperatures.

Recently, the plant polyphenols have attracted much attention for membrane modification, especially in surface coating application. In this study, the synthesis of catechol-amine coating solutions was evaluated at different pH conditions and with different concentrations of tannic acid and tetraethylenepentamine in order to determine the relationship between chemical structure and mechanism in the oxidation reaction. The reactivity of catechol and amine groups in the formulation was measured using UV-Vis spectroscopy and observation of the change in colour of the coating solutions. Then, the deposition of catechol-amine coating solutions was applied onto the hydrophobic polyvinylidene fluoride (PVDF) membrane. The formulation results show significant differences in alkaline conditions, revealing the role of catechol groups in the oxidation of polyphenolics. The reactions of quinone and amines to form crosslinks by Michael addition and Schiff base reactions were observed at different concentrations of each compound in coating solution. In addition, the negative charge of hydrophilic and underwater oleophobic-coated PVDF membrane was confirmed by surface zeta potential analysis. The morphological surface of modified membrane is rougher due to that coating deposition was also examined using scanning electron microscopy (SEM). Furthermore, the performance of modified membrane is comparable with the commercial hydrophilic membrane in terms of fluxes and separation efficiency of emulsion solution.

In this work, coconut shell activated carbon (CSAC) electrode was evaluated to remove copper ion via electrochemical processes. CSAC electrode and graphite were applied as the cathode and the anode, respectively. The reusability of the electrode, the effects of initial pH, applied voltage and initial concentration were studied. The electrochemical process was carried out for 3 h of treatment time, and the electrodes (anode and cathode) were separated by 1 cm. The results revealed that CSAC is proven as a reusable electrode to remove copper ion, up to 99% of removal efficiency from an initial concentration of 50 ppm after it had been used three times. From the observation, the removal efficiency was optimum at an initial pH of 4.33 (without any initial pH adjustment). The applied voltage at 8 V showed a higher removal efficiency of copper ion compared to at 5 V.

This study investigates the optimal operational conditions for oxidative degradation of methyl orange (MO) in heterogeneous Fenton-like reaction using iron-immobilized montmorillonite KSF (Fe-MKSF) composites. Central composite design (CCD) experiments were used to determine the effects of four operational variables; pH solution, catalyst dosage, concentration of H2O2 and initial concentration of methyl orange dye (MO) on the percentage of MO removal. Based on the analysis of variance (ANOVA), the model illustrated high correlation coefficient (R2) of 0.9589 which demonstrated approximately 96% of target function variation. The optimal operational conditions were found to be at 2.8 pH solution, 0.8g/L catalyst dosage, 15 mM H2O2 concentration and 25 mg/L MO initial concentration which subsequently resulted in 98% of MO removal. Moreover, the experimental values obtained were in good agreement with the values predicted from the model, with relatively slight differences of 1.24%. Such findings shown significant interaction between four operational variables towards MO removal during the heterogeneous Fenton-like reaction using Fe-MKSF composites.

The pollution of water by effluents from dye industries is a widely established environmental and health problem that requires new insights and urgent attention. In this study, methylene blue (MB) and acid blue 29 (AB29) dyes were oxidatively degraded under the dark-Fenton process conditions using abundant electric arc furnace steel slag activated by sulfuric acid (S-EAF). The severity of the oxidative degradation conditions was screened under conditions at 50–150 mg/l dyes solution initial concentration, the H2O2 concentration range of 2–12 mM, and pH from 2 to 7. The results show that predominant crystalline ferrous ions on the S-EAF catalyst stimulated the decomposition of the H2O2, to enhance the generation of •OH radicals, which promoted oxidation of the dyes to realize 95% and 82% removal under 6 mM (AB29), and 8 mM (MB) H2O2 concentration at 30 °C. The pseudo-first-order kinetic sufficiently described the experimental data and application of the Langmuir-Hinshelwood model validated the dominant role of surface reaction, which was collaborated by the activation energy. The S-EAF catalyst sustained the oxidative degradation for seven cycles with minor leaching of irons (Fe).

This study aims to explore the feasibility of using iron slag derived from an electric arc furnace (EAFS) as a catalyst to degrade Reactive Black 5 (RB5). Raw EAFS (R-EAFS) subjected to 0.1 M NaOH solution treatment and thermal treatment was denoted as activated EAFS (A-EAFS). A-EAFS was characterized and examined for its capability to degrade RB5 in a dark-batch reaction under different catalyst dosages (0.01–0.06 g), H 2 O 2 dosages (2–12 mM), initial pH values (2–7), initial concentrations (25–150 ppm), and reaction temperatures (303–323 K). The optimal conditions (94% within 60 min) for RB5 degradation were 0.2 g L −1 , 8 mM H 2 O 2 , and pH 3. The degradation rate of A-EAFS for RB5 exceeded 94%, which was higher than that of R-EAFS. Recycling of A-EAFS after 10 reuses suggested that this stability is ascribed to the regeneration of the major constituent's ferrous ion magnetite and maghemite to decompose H 2 O 2 into hydroxyl radical catalytically. Therefore, A-EAFS is an alternative heterogeneous catalyst in the abatement of organic dyes from polluted water through a heterogeneous Fenton-like reaction.

The Fe2+/modified silica catalysts have been substituted with four types of transition metals such as Fe3+, Cr3+, Mn3+ and Mo. The catalytic activity of these catalysts has been tested for the oxidative degradation of Reactive Black 5 (RB5) at 30°C and pH 4.5. The substituted Fe2+/modified silica with Fe3+ (Fe2+:Fe3+/ m-SiO2) exhibited the highest catalytic performance compared to others transition metals by degrading the RB5 nearly to 95%. This catalyst possessed on high stability by maintaining its performance during the three successive cycles of reaction. These findings can be ascribed to the plausible enhancement in the formation of hydroxyl radicals (HO●) due to the effective redox between Fe2+ and Fe3+

CO2 compression systems are commonly designed assuming negligible amount of impurities in CO2 fluid, it is of practical interest to evaluate the impact of impurities in oxy-fuel streams on the compression power requirements. Compared to more traditional postcombustion and pre-combustion capture methods, oxy-fuel technology produces a CO2 stream with relatively high concentration of impurities that may require partial or a high level of removal and whose presence can be expected to increase the costs of CO2 compression. Four types of compression technologies employed include four-stage compressor with 4 intercoolers, single-stage supersonic shockwave compressor, three-stage compressor combined with subcritical liquefaction and pumping and three-stage compressor combined with supercritical liquefaction and pumping. The study depicts that decrement of the impurities content from 15 to 0.7%v/v in the CO2 streams reduced the total compression power in the compression system. The study also concludes that three-stage compressor combined with subcritical liquefaction and pumping can potentially offer higher efficiency than four-stage compressor with 4 intercoolers for almost pure CO2 streams. In the case of raw oxy-fuel mixture, that carries relatively large amount of impurities, subcritical liquefaction proved to be less feasible, while supercritical liquefaction efficiency is only marginally lower than that in the four-stage compressor with 4 intercoolers.

The main purpose of this study is to identify the optimum multistage compression strategies for minimising the compression and intercooler power requirements for pure CO2 stream. An analytical model based on thermodynamics principles is developed and applied to determine the power requirements for various compression strategies for pure CO2 stream. The compression options examined include conventional multistage integrally geared centrifugal compressors (option A), supersonic shockwave compressors (option B) and multistage compression combined with subcritical (option C) and supercritical liquefaction (option D) and pumping. In the case of determining the power demand for inter-stage cooling and liquefaction, a thermodynamic model based on Carnot refrigeration cycle is applied. From the previous study by [1], the power demand for inter-stage cooling duty was assumed to have been neglected. However, based on the present study, the inter-stage cooling duty is predicted to be significantly higher and contributes approximately 30% of the total power requirement for compression options A, C and D, while reaches 58% when applied to option B. It is also found that compression option C can offer higher efficiency than other compression strategies, while supercritical liquefaction efficiency is only marginally higher than that in the compression option A.

In this work, detailed investigation on the optimization of acid orange II (AOII) degradation using Fe3-xMnxO4 catalyst in UV assisted Fenton-like reaction was performed. The Central Composite Design (CCD) based on Response Surface Methodology (RSM) with four independent operational parameters (catalyst dosage, oxidant concentration, pH and UV irradiation) and one response (percentage of AOII removal) was applied for statistical and optimization analysis. The maximum AOII removal (~100%) was found at optimal conditions of 0.4 g/L catalyst dosage, 35 mM oxidant concentration, pH 2.6 and 3 x 9W UVC. Interestingly, validation of these optimal conditions was confirmed by the experimental findings of having less than 2% absolute deviation. Such findings confer that the derived empirical quadratic model was in good agreement with the experimental findings.

This work presents the iron oxide recovery from electric arc furnace slag with different temperature and time using acid leaching method. The results showed that formation of iron oxide from electric arc furnace (IO-EAFS) was influenced by the temperature and time of heating. This is evidenced by constant acid concentration and liquid to solid ratio, 5 hours of heating time was exhibited the highest amount of iron ion in extracted solution. The maximum of iron extract in heating temperature was at 100 °C. Throughout the characterization using Scanning Electron Microscopy (SEM), the iron oxide illustrated the microstructures were agglomerates predominantly with irregular shapes and XRD results further colobrated the presence of hematite combined with other metal oxide exists in the IO-EAFS. From the TGA analysis, it was identified that the recovered iron oxide was totally decomposed at 525°C. This results indicate that electric arc furnace slag is potential material of iron oxide for the future appliction.

In this study, the influence of manganese substitution on the photocatalytic activity of heterogeneous Fe3-xMnxO4 catalyst were investigated. The Fe3-xMnxO4 catalysts were synthesized through co-precipitation method at varies manganese (Mn) substitution ratio (x) of 0, 0.1, 0.2, 0.3, 0.4 and 0.5, respectively. The photocatalytic performance of the resultant catalysts were tested in photo Fenton-like degradation of AOII dye in the presence of 22Mm H2O2 at initial pH of 3. Interestingly, discoloration of 95.9% AOII was achieved at optimized x value of 0.3. Enhancement of nearly 98% was observed compared to pristine catalyst (x=0) which was able to degrade up to 48.4% only. In addition, it also demonstrated that the AOII degradation kinetic using Fe3-xMnxO4 catalyst at x=0.3 by photo Fenton-like reaction was fitted well with the first order reaction kinetic (k = 0.018 min-1 and R2 = 0.9862). Thus, it can be suggested that the substitution of Mn into the matrix of iron oxide provides a positive influence in enhancing the overall photocatalytic peformance of heterogeneous Fe3-xMnxO4 catalyst during the photo Fenton-like reaction.

In this work, an activated electric arc furnace slag (A-EAFS) was investigated as an effective Fenton catalyst for the photodegradation of methylene blue (MB) and acid blue 29 (AB29). Fourier transform infrared spectroscopy and UV–visible absorption analyses indicated that A-EAFS offers additional Fe 3 O 4 because of the changes in the iron oxide phase and the favorable response to visible light. It has been found that the highest degradation efficiency can reach up to 94% for MB under optimal conditions of 1 g L −1 of A-EAFS, 20 mM H 2 O 2 , and pH 3. The optimal conditions for AB29 were 0.1 g L −1 A-EAFS, 4 mM H 2 O 2 , and pH 3 to reach 98% degradation efficiency. Visible light enhanced the degradation of both dyes. In addition, A-EAFS, could be easily separated magnetically, exhibited good chemical stability after seven successive photodegradation cycles.

Pulp and paper industry generates large volumes of highly heterogeneous wastewaters containing compounds from wood or other raw material, process chemicals as well as compounds formed during processing. This study has designed a fixed film reactor which uses the concept of biological attached growth treatment to treat the pulp and paper wastewater. The laboratory-scale fixed film reactor is designed with a circular column of 120 cm height, 15 cm inner diameter and a total volume of 23000 cm 3 . The column which constructed in PVC was packed with PVC plastic pipes which were cut into the size of 4.5 cm length and 3 cm diameter and had a specific surface area of 42 cm 2 . An amount of 150 PVC plastic pipes were placed in the digester. The system was found could remove about 53% of BOD5 and 89% COD. The treatability constant corresponding to the depth of the reactor, k in this study is found to be 0.038 gal/min 0.5 ft and the observed reaction rate constant, K is 0.04 ft/d at 25°C. This fixed-film reactor could be operated as a trickling filter.

In this work, the removal of a basic dye, methylene blue (MB) from aqueous solution using NaOH-modified rejected tea (N-RT) was investigated. Equilibrium adsorption and kinetics were studied. The results confirmed that the adsorption isotherm data fitted well to Langmuir isotherm with monolayer adsorption capacity of 242.11 mg/g. The kinetics of MB adsorption process was found to follow pseudo-second-order rate expression. The results suggested that the N-RT would be an excellent alternative for the removal of MB by adsorption process.

Iron–immobilized montmorillonite KSF (Fe-MKSF) has been recognized as promising catalyst in degrading persistence organic contaminants. However, detailed mechanistic insight during the catalysis which involving the formation and identification of radical species were remained indeterminate due to complex reaction. Inspiring by this gap, iron-immobilized clay (Fe-MKSF) was synthesized and used as heterogeneous catalyst in the oxidative degradation of methyl orange (MO) solution. Identification of radical species were determined through the inclusion of different types of radical scavenging agent during the Fenton-like reaction at optimum condition. Interestingly, dominant radical species were found to be hydroperoxyl radicals (•OOH) which subsequently followed by hydroxyl radicals (•OH) during the catalysis. Based on the percentage of MO removal, it was suggested that approximately 88% of the •OOH radicals existed at the interface of catalyst while 39% presence in bulk solution. Meanwhile, the interface •OH radicals promoted 38% of MO removal, whilst 4% by the bulk •OH radicals. Hence, these findings have conveyed novel insight on detailed radicals' identification as well as its' interaction during the catalysis.

The adsorption of methylene blue (MB) from aqueous solution using a low-cost adsorbent, rejected tea (RT), has been studied by batch adsorption technique. The adsorption experiments were carried out under different conditions of initial concentration (50-500 mg/L), solution pH 3-12, RT dose (0.05-1g) and temperature (30-50 degrees C). The equilibrium data were fitted to Langmuir and Freundlich isotherms and the equilibrium adsorption was best described by the Langmuir isotherm model with maximum monolayer adsorption capacities found to be 147, 154 and 156 mg/g at 30, 40 and 50 degrees C, respectively. Three kinetic models, pseudo-first-order, pseudo-second-order and intraparticle diffusion were employed to describe the adsorption mechanism. The experimental results showed that the pseudo-second-order equation is the best model that describes the adsorption behavior with the coefficient of correlation R(2)or=0.99. The results suggested that RT has high potential to be used as effective adsorbent for MB removal.

This present study was conducted to investigate the effectiveness of catalytic wet peroxide oxidation (CWPO) process using photo-Fenton method and the used of mining sand as support catalyst as well as to determine the optimum parameters and effect of catalyst wt%, pH, H2O2 concentration, initial dye concentration and catalyst dosage on RB 5 degradation. The Fe/mining sand was prepared by impregnation technique and a solar degradation of RB 5 carried out by mean photo-Fenton reaction promoted by solar energy. The dye degradation was monitored during the experimental runs through UV/Vis spectrophotometer. In this process, the reaction condition were optimized at 0.4 of catalyst wt%, pH 2, 4 mM of H2O2 concentration and 0.5 g of catalyst dosage which achieved degradation efficiency at 100% for the three experiments except catalyst dosage which achieved 97.54% respectively within 180 min. The degradation of RB 5 also decreased with the increasing of dye concentration with 10 mg/L achieved the optimum degrada...

Composite material has been growing rapidly throughout the year for its unique properties in comparisons with metal. Recently, there has been a growth on studying the way to reduce the delamination failure, which is the primary challenge on laminated fibre composite. This failure can degrade the strength of composite materials, hence loses its function. In this review, database search was performed using the keywords search on "interlaminar fracture toughness", "double cantilever beam", "delamination resistance" and "Mode-I GIC". The searches were performed on Google Scholar, Scopus and Web of Science with further cross-referencing with other databases. Most relevant studies were selected for review and referencing by the author. This review paper gives a brief explanation on Mode-I interlaminar fracture toughness of composite material. This fracture mode is the most common modes on studying the delamination failure.

The feasibility of using guava waste activated carbon (GWAC) for the methylene blue (MB) adsorption has been investigated. The GWAC was prepared using simple thermochemical activation method. The comparison on adsorption performance between GWAC and commercial activated carbon (CAC) were conducted using the batch adsorption study to determine the adsorption capacity for both adsorbents. The adsorption study was carried out at different initial concentrations of MB (50–500 mg/L) at temperature of 30 °C for 5 hours. The equilibrium data were analyzed using Langmuir and Freundlich isotherm models followed by kinetics study. The experimental data for both adsorbents were fitted well with Langmuir isotherm with a maximum monolayer adsorption capacity of 250.00 mg/g and 333.33 mg/g for GWAC and CAC, respectively. The peudo-second order kinetics was the best for the adsorption of MB by GWAC and CAC with good correlation. The results demonstrated that GWAC is an effective adsorbent for removal of MB and have potential to replace the commercial activated carbon for removal of dyes from wastewater.

The aim of this study is to compare the adsorption capacity of Remazol Brilliant Blue R (RBBR) onto three different coal-based adsorbents namely, untreated bottom ash (BA), H 2 O 2 -treated BA and physical-activated BA. The removal of RBBR was determined over a concentration range of 50–500 ppm using batch adsorption experiment at room temperature. The percentage removal of RBBR was decreased with the increase of initial concentration. The comparison of percentage removal of RBBR onto the various adsorbents followed the trend: physical-activated BA > H 2 O 2 -treated BA > untreated BA. In addition, the adsorption isotherm constant reveals that physical-activated BA gives the highest adsorption capacity of RBBR. Result shows that the adsorption mechanisms of RBBR onto the adsorbents studied are well presented by both Langmuir and Freundlich isotherms.