ASEAN Journal of Chemical Engineering

Sulphamic Acid Corrosion Inhibition: A review

2024-08-30T15:00:38+07:00

Sulphamic acid solutions are frequently employed in industrial equipment cleaning, descaling, and other processes, such as acidizing low-temperature carbonate reservoirs. Several researchers have reported the inhibition of corrosion of different metals and alloys in sulphamic acid using inhibitors like tryptophan, olive leaf, azo dyes, chitosan, Juniperus, cystine, s-containing amino acids, etc. Sulphamic acid is soluble in water and is classified as a strong inorganic acid in solution. Still, its corrosiveness is significantly lower than other acids, such as sulphuric acid and hydrochloric acid. Sulphamic acid and inorganic acid cleaners based on sulphamic acid are used extensively in diversified cleaning applications. They are superior to other mineral acids due to lower corrosion rates and the absence of corrosive fumes evolution. For this reason, mild and stainless-steel cleaning employs sulphamic acid. Nevertheless, the application of sulphamic acid in industrial cleaning is only partially without its drawbacks, as the cleaning action usually leads to dissolution and loss of base metals. Industrial practice includes adding corrosion inhibitors to minimize equipment corrosion damage. The current review paper summarises recent research on sulphamic acid corrosion inhibition. It summarizes the various corrosion inhibitors employed to mitigate corrosion in various pieces of equipment made of metals or metal alloys exposed to sulphamic acid in different conditions. The researchers employed weight loss, electrochemical methods, and surface characterizations. In literature and practice, the usual concentration of sulphamic acid for cleaning is 5 – 10 wt. % at a temperature range of 55 – 65 ℃. The inhibition efficiencies observed varied from 84 – 97.3 %. The examinations include studies of the effects of temperature, concentration, immersion time, and stirring velocity.

Statistical Analysis of Activation Factors for Coffee Husk derived Activated Carbon on Chromium (VI) Adsorption and Carbon yield

2024-08-30T15:00:39+07:00

Coffee husk waste, an abundant waste material in Vietnam, has been utilized to produce activated carbon. However, the single and interactional effects of activation factors for pyrolysis of coffee husk waste have not been studied well. This research proposed a fully statistical strategy including Box-Behnken experimental design, analysis of variance, regression diagnostics, influence degree, optimization and test of good-fitness, analysis of activated carbon’s surface, and aimed to explore activation factors of impregnation ratio (IR) between H₃PO₄ and the biomass, activation temperature (AT) and time on Cr(VI) adsorption and carbon yield. The antagonistic effects of first-order AT and second-order IR contributed 75.91% of total influence factors and had the greatest impact on carbon yield. In contrast, the second-order AT, IR and the first-order IR, AT, their interaction accounting for 94.77%, had a statistically significant influence on Cr(VI) adsorption capacity. The optimal values of 35% IR, 540^oC and 72 minutes could give 72.67±4.13% carbon yield, 104.13±7.64 mg Cr(VI) g^-1, and a specific surface area of 1896 m² g^-1 due to an abundance of micropores, mesopores and hydroxyl, carbonyl and carboxylic groups on the biochar’s surface. These findings suggest that the coffee husk waste-derived activated carbon may be a promising adsorbent for Cr(VI) and other small to medium-sized compounds from water, and the second-order polynomial regression model can be used to interpret the pyrolysis conditions to reduce preparation time and overall cost.

Effect of Graphene Oxide Sealing on the Corrosion Resistance of Anodized Aluminum Oxide

2024-08-30T15:00:39+07:00

Aluminum alloy materials are widely used in aerospace, construction industry, automotive, and other fields due to their low cost and typical properties, including high strength-to-weight ratio and good corrosion resistance. The role of the anodization process that forms anodic aluminum oxide (AAO) can improve corrosion resistance, but the aluminum surface is pivoted after the anodization process. This study was conducted to determine the effect of GO-sealed on the corrosion resistance of AAO. The results show that anodized aluminum with GO-sealed performs better corrosion resistance as indicated by higher R_porous and R_solid values when compared to unsealed anodized aluminum. Furthermore, anodized aluminum with GO-sealed has a smoother surface and harder than unsealed aluminum. It is indicated by surface characterization and hardness test.

Kinetic Study of Biodiesel Purification from Used Cooking Oil Using Activated Carbon

2024-08-30T15:00:40+07:00

Used cooking oil (UCO) is a hazardous pollutant that leads to environmental problems. In general, UCO was discharged directly into the water, although it has the potential to be processed. One alternative process of UCO is its potency as the main material of biodiesel production. Biodiesel is produced via a transesterification process, during which the reaction between UCO and alcohol occurs. The results obtained from this reaction include biodiesel and glycerol. In this study, pure biodiesel was obtained by purification using the adsorption process. The adsorbent was activated carbon from coconut shells that were contacted at a certain concentration and contact time. The adsorbent concentrations were varied from 3, 6, 9, and 12(w/w) addition, while the contact times were 30, 45, 60, 75, and 90 min. The crude biodiesel adsorption was carried out at 90^oC. FFA removal increased with increasing adsorbent concentration and contact time. With 12% adsorbent addition, FFA was removed up to 64.91% in a 90 min adsorption process. The kinetics of the adsorption process were analyzed using several kinetics models, either in the linear or nonlinear form. The best kinetic fit in this process was obtained using a nonlinear pseudo-second-order model.

Adsorption of Crystal Violet Dye onto Anionic Polyacrylamide-Modified Graphite: Equilibrium, Kinetics, and Mechanism

2024-08-31T12:22:57+07:00

The textile industry is a major source of wastewater with a high concentration of organic and inorganic chemicals, including dyes. In this study, exfoliated graphite was modified using surfactants Sodium dodecyle sulfate (SDS) and N-cetyl-N,N,N- trimethyl ammonium bromide (CTAB) as well as coagulant anionic polyacrylamide (APAM) to improve the adsorption capacity of pure exfoliated graphite to treat simulated crystal violet (CV) dye. This work also studied the effect of contact time, Dye Concentration, pH and adsorbent loading. Furthermore, adsorption kinetics were investigated by varying contact time and dye concentration. It was observed that modification with surfactants SDS and CTAB did not show appreciable results. However, modification of graphite flakes with APAM resulted in 89.27% removal efficiency compared to unmodified graphite flakes. The graphite flakes were characterized using XRF analysis, BET surface area, and FTIR analysis. UV/Vis-Spectrometer analyzed the concentration of dye solution at a wavelength of 592nm. The availability of active sites and its ability to regenerate the exfoliated graphite made it a potential candidate for the adsorption of CV dye. Moreover, Langmuir and Freundlich adsorption models were applied to investigate dye adsorption behavior. It was observed that the Langmuir model provides the best fit for this system.

Synthesis of Green Diesel from Non-edible Kapok (Ceiba petandra) Seed Oil via Hydrotreating Process Using Sulfided Ni-Mo/Al2O3 Catalysts

2024-08-30T15:00:41+07:00

The demand for environmentally friendly and renewable fuels will keep increasing due to the accelerated climate change worldwide. Ceiba pentandra seed oil is a promising feedstock for renewable fuel since it possesses major fatty acid components with similar skeletal structure to diesel-range hydrocarbons. Nevertheless, its direct utilization will potentially cause problems due to the cyclopropenoid group and its high viscosity. In this research, hydrotreating processes over bimetallic sulfided Ni-Mo/g-Al₂O₃ catalysts were performed to convert the kapok seed oil into green diesel, with lower cloud points compared to those derived from other common vegetable oils. The hydrotreating process was needed not only to eliminate cyclopropenoid and oxygen contents but also to reduce the unsaturated bonds and, at the same time, increase its H/C ratio. The BET measurement showed the catalyst surface area of 144 m²/g, while the existence of NiS and MoS₂ as active sites on its surface was detected by XRD analysis. The TEM analysis indicated that sulfided Ni and Mo were dispersed reasonably well, with a little aggregation, on the catalyst surface. The most well-performed catalyst (with Ni:Mo ratio of 0.2:1 and K:P promoter ratio 0.5:1) successfully synthesized bio-hydrocarbons (with desirable C₁₅-C₁₉ diesel range) with the conversion of almost 96%, with no remaining cyclopropenoid content.

Experimental Investigation of Silica Nanoparticle Assisted Lignosulfonate Surfactant for Chemical Enhanced Oil Recovery (EOR) Flooding

2024-08-31T12:22:01+07:00

There has been significant interest in incorporating nanoparticles into surfactants to enhance the performance of chemical-enhanced oil recovery. This interest has arisen due to attempts to mitigate the decline in surfactant efficiency caused by various environmental factors within the reservoir. The primary objective of this study was to investigate how silica nanoparticles (SNP), combined with formulated sodium lignosulfonate (FSLS) surfactants, can improve oil recovery from reservoirs. In this paper, we conducted an experimental study to assess the impact of SNP when mixed with FSLS surfactants. The aim was to evaluate whether SNP alters the characteristics of FSLS surfactants and to determine SNP's potential to enhance oil recovery. We conducted experiments to measure compatibility, interfacial tension, and core flooding. We identified the optimal conditions for an FSLS 1% wt + SNP 0.1% wt solution for chemical flooding test based on the experimental results. The chemical flooding results showed a significantly higher recovery factor (RF) in the presence of SNP, with a recovery of 60% of the initial oil in place (IOIP), compared to only FSLS, which had an RF of 23.53% IOIP. The resulting interfacial tension (IFT) value was 10^-4 - 10^-3 mN/m. The solutions showed good stability in a single phase, did not precipitate, and appeared clear. Therefore, using SNP combined with FSLS surfactants demonstrates excellent potential for enhancing chemical-enhanced oil recovery methods.

Exploring Microwave-Assisted Pyrolysis of Sargassum sp. for Optimal Process Parameters and Product Insights

2024-08-30T15:00:41+07:00

Microwave-assisted pyrolysis (MAP) offers a promising alternative to fast pyrolysis for scaling up biomass conversion processes, facilitating accelerated reactions without significant temperature elevation. This study investigated the optimum process parameters for MAP of Sargassum sp., the predominant macroalgae in Indonesia. Parameters explored included Sargassum sp. particle sizes (10-40, 40-70, 70-100, >100 mesh), final temperatures (300, 350, 400, 450 °C), and coconut activated carbon (CAC)-to-feedstock ratios (1:2, 1:1, 3:2), with CAC acted as a microwave absorber. Experimental results indicated that the highest volatile yield (57.64%) occurred at a 40-70 mesh particle size and a final temperature of 450 °C, yielding bio-oil and gas at 24.88% and 32.76%, respectively. Increasing CAC loading enhanced bio-oil and char yields while reduced gas production, with a 1:1 ratio, yielded an optimal calorific value. Bio-oil density ranged from 0.9557 to 0.9968 g/mL. Gas chromatography-mass spectrometry (GC-MS) analysis revealed significant sterol derivatives and butanoic acid in the bio-oil, with lower concentrations of N-aromatic compounds. Fourier-transform infrared spectroscopy (FTIR) identified key peaks characteristic of aromatic (1400 and 1500 cm^-1), carbonyl (1700 cm^-1), C-N bonds (2100-2200 cm^‑1), amide and amine (3300-3400 cm^-1), and hydroxyl and carboxylic acid (3450 cm^‑1). These findings underscored the efficacy of MAP in achieving high volatile yields at relatively moderate temperatures compared to conventional methods. Moreover, butanoic acid's presence in the bio-oil highlighted its potential as a valuable resource for safe food preservation and chemical synthesis. However, detecting sterol derivatives and complex N-aromatic compounds suggested incomplete decomposition at 350 °C.

Harnessing Microalgae Photobioreactors to Address Rising Sludge and Fouling Challenges in Membrane Bioreactors

2024-08-30T15:00:42+07:00

This study explored the application of microalgal engineering in a photobioreactor to mitigate rising sludge and fouling issues in a Wastewater Treatment Plant (WWTP). By introducing microalgae into the activated sludge of a Moving Bed Biofilm Reactor (MBBR), this study aimed to enhance the dissolved oxygen content within the MBBR, which was a critical factor for optimizing the reduction of Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD) in wastewater. During the microalgae cultivation phase, Chlorella sp. was cultured with adding nutrients, including urea and TSP. Upon reaching a sufficient Mixed Liquor Suspended Solids (MLSS) concentration, microalgae were inoculated into the MBBR. The research results demonstrated an improvement in the quality of the effluent and a reduction in rising sludge within the clarifier, coinciding with an increase in dissolved oxygen content exceeding 2 mg/L. Cost-benefit analysis revealed a significant reduction in WWTP operational costs, primarily due to the discontinuation of two blowers that were previously operated. This study encourages the utilization of microalgae in MBBRs as a potential solution to reduce operational costs in the wastewater treatment industry.

Effect of Osmotic Pressure Gradient on Concentration of Treated Tannery Effluent in Forward Osmosis

2024-08-30T15:00:43+07:00

In this study, Forward Osmosis (FO) process is investigated for concentrating three different types of synthetic secondary treated tannery effluents (FS1, FS2 and FS3) as feed solution and using NaCl solution as draw solution. Operating FO at low osmotic pressure gradient (∆Π_low) of 9.33 ± 0.7 bars and high osmotic pressure gradient (∆Π_high) of 20.63 ± 0.7 bars, for concentration of FS1, FS2, and FS3 respectively, was evaluated in terms of flux (J_w), flux decline ratio (FDR), percentage increase in feed solution concentration (CF) and solute rejection (SR). Results show that operating FO at ∆Π_high gave higher J_w and lower FDR as compared to operating FO at ∆Π_low, irrespective of feed solution composition. However operating FO at ∆Π_low provided higher J_w and lower FDR for FS1 (4.54 LMH and 36.1%) as compared to FS2 (4.15 LMH and 40.9%) and FS3 (3.20 LMH and 45.35%) whereas operating FO at ∆Π_high provided higher J_w and lower FDR for FS3 (6.18 LMH and 26.88%) and FS2 (6.16 LMH and 27.84%) as compared to FS1 (5.7 LMH and 32.52%). CF and SR were higher for experiments performed at ∆Π_high as compared to ∆Π_low, irrespective of feed solution composition. Solutes like magnesium and chromium had good rejection (>80%) at ∆Π_high and ∆Π_low, irrespective of FS type. Potassium and Ammonium had low rejection at ∆Π_high and ∆Π_low for FS3, FS2 and FS1 respectively. Essentially, by emphasizing osmotic pressure gradient as a critical component, this study suggested a methodical strategy to researching the FO process.