Effect of hydrophilic coating for membrane assisted air diffuser for Chlorella vulgaris cultivation

Microalgae cultivation has high potential in capturing atmospheric carbon dioxide (CO2) but are limited by poor CO2 mass transfer to the algae. Therefore, improving mass transfer by increasing total contact area of gas-liquid through minimizing bubble size formed is investigated. In this project, the effect of polyether block amide (PEBAX® 1657) coating (i.e. different concentration and coating cycle) on polyvinylidenefluoride (PVDF) membrane surface properties are investigated and their impact on algae cultivation are evaluated using Chlorella vulgaris for duration of 14 days. The presence of functional groups from PEBAX coating showed the success of coating process and membrane hydrophilicity is improved from 111.19 ± 0.10° to 40.57 ± 1.29° when PEBAX 2.0 wt% is used. Membrane porosity is reduced when PEBAX concentration and number of coating cycle increased. Concentration of biomass is the highest (1.107 g/L) when PVDF/PEBAX 2.0 wt% is used, likely because of small size of CO2 bubbles delivered into culture medium

Characteristics of Ammonia Adsorption on Various Sizes of Calcium Carbonate Microparticles from Chicken Eggshell Waste

The purpose of this study was to synthesize carbon biochar microparticles from pomegranate peel waste for ammonia adsorption. Experiments were done by carbonization of pomegranate peel waste. The carbonized materials were then milled and sieved to get carbon biochar microparticles with a specific size (500, 1000, and 2000 μm). The particles were then characterized using a microscope and infrared spectroscopy (FTIR) to identify particle morphology and functional groups, respectively. The prepared particles were then used for the ammonia adsorption process, tested, and compared with ten isotherm models (such as Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Jovanovic, Halseys, Harkin-Jura, Flory-Huggins, Fowler-Guggenheim, and Hill-Deboer) to identify the adsorption mechanism. The pseudo-second-order kinetic model was suggested for describing the adsorption process that occurs to form a complex multilayer layer between the adsorbent and the adsorbate. This result is supported by the investigation of the adsorption isotherm model which found that all particle sizes have a pattern where a multilayer layer is formed due to the distribution of pores. Layer formation during the adsorption process involves physisorption and chemisorption with spontaneous and endothermic systems. Ukuran partikel mengkonfirmasi adanya perbedaan kemampuan yang ditandai dengan nilai kapasitas adsorpsi. The particle size confirms the difference in ability as indicated by the adsorption capacity value. The smaller the particle size, the greater the maximum capacity because it has a large surface area. On the other hand, the smaller the particle size, the greater the maximum capacity because it has a large surface area. This study shows that the use of eggshell waste has the potential. This study shows that the use of eggshell waste has the potential to be used as an adsorbent and supports the Sustainable Development Goals (SDGs) program

Development of membrane material for oily wastewater treatment: a review

Our world is facing continued challenges of environmental and ecological pollutions due to human and industrial activities. One of the major threats is oily wastewater mainly discharged from oil fields, refineries, automobile, palm oil industries, and many others. Membrane-based technology offers an almost complete separation of oil from water. However, the technology is facing the challenge of maintaining performance over long periods of operation caused by membrane fouling as a result of interaction between oil droplets and the membrane surface. This attracts research interest mainly on developing customized polymeric, ceramic well as a metallic-based membrane material for improved performance. This paper reviews the recent advances of membrane material developments with the focus on methods of improving the surface chemistry, structure, and hydrodynamics and their implication on the filtration performances

Combinación de ozono y nanopartículas magnéticas verdes para la degradación de azul de metileno en agua residual sintética textil

Trabajo de investigaciónSe usaron nanopartículas de magnetita verdes en un proceso de ozonización para remoción del colorante azul de metileno proveniente agua residual sintética textil. La concentración inicial del contaminante fue de 2mg/L. Se obtuvo una capacidad máxima de adsorción sobre el material de 0.0086mg/g debida a la modelación cinética e isotermas. Finalmente se encontró un porcentaje de remoción de 87.02 usando ozonización catalítica.RESUMEN 1. INTRODUCCIÓN 2. PLANTEAMIENTO Y FORMULACIÓN DEL PROBLEMA 3. JUSTIFICACIÓN 4. OBJETIVOS 5. ESTADO DEL ARTE 6. ANTECEDENTES 7. MARCO DE REFERENCIA 8. ALCANCE Y LIMITACIONES 9. METODOLOGÍA 10. RESULTADOS CONCLUSIONES RECOMENDACIONES REFERENCIAS ANEXOSPregradoIngeniero Civi

Patterned membrane in an energy-efficient tilted panel filtration system for fouling control in activated sludge filtration

A membrane bioreactor enhances the overall biological performance of a conventional activated sludge system for wastewater treatment by producing high-quality effluent suitable for reuse. However, membrane fouling hinders the widespread application of membrane bioreactors by reducing the hydraulic performance, shortening membrane lifespan, and increasing the operational costs for membrane fouling management. This study assesses the combined effect of membrane surface corrugation and a tilted panel in enhancing the impact of air bubbling for membrane fouling control in activated sludge filtration, applicable for membrane bioreactors. The filterability performance of such a system was further tested under variable parameters: Filtration cycle, aeration rate, and intermittent aeration. Results show that a combination of surface corrugation and panel tilting enhances the impact of aeration and leads to 87% permeance increment. The results of the parametric study shows that the highest permeance was achieved under short filtration-relaxation cycle of 5 min, high aeration rate of 1.5 L/min, and short switching period of 2.5 min, to yield the permeances of 465 ± 18, 447 ± 2, and 369 ± 9 L/(m2h bar), respectively. The high permeances lead to higher operational flux that helps to lower the membrane area as well as energy consumption. Initial estimation of the fully aerated system yields the energy input of 0.152 kWh/m3, much lower than data from the full-scale references of <0.4 kWh/m3. Further energy savings and a lower system footprint can still be achieved by applying the two-sided panel with a switching system, which will be addressed in the future

Activated carbon and halloysite nanotubes membrane for CO2 and CH4 separation

In this study, mixed matrix membranes (MMMs) were prepared where activated carbon and halloysite nanotubes with a loading of 1 wt% is incorporated into the polysulfone membrane, and the performance of each membrane was investigated. The morphological properties, mechanical strength and their correlations with the gas separation performance for CO2 and CH4 for halloysite-mixed matrix membrane (MMMs-HNT) and activated carbon-mixed matrix membrane (MMMs-AC) was studied by using Scanning Electron Microscopy (SEM-EDX), tensile test and gas permeation test. From the characterization of MMMs, SEM shows an increase of 30.77% on the thickness of the dense layer of MMMs-HNTs compared to neat membrane and MMMs-AC. The EDX results also showed that HNTs evenly distributed in the polymeric matrix without any sign of agglomeration. Elongation at the break for MMMs-HNTs also decreases to 11.38%. The gas separation performance for MMMs-HNTs increased by about 55.43% compared to MMMs-AC at 2 bar. Furthermore, MMMs-HNTs also showed in increase in the selectivity of membrane towards CO2 and CH4 from 0.82 to 15.83 at 2 bar. In conclusion, the addition of 1 wt% of HNTs into PSF polymeric matrix showed a better permeance of CO2 and a greater selectivity compared to the neat membrane and the MMMs-AC and thus is the optimum inorganic filler for the mixed matrix membrane

Pemodelan Unjuk Kerja Biofilter Dalam Penyisihan H2S Dan NH3

Percobaan penyisihan H2S dan NH3 menggunakan biofilter dalam skala laboratorium telah dilaksanakan dengan menggunakan dua jenis media (limbah padat karet dan seraut sawit) dan konsorsium mikroorganisme yang melekat secara alami dalam media. Tujuan dari percobaan ini adalah untuk menentukan kinerja biofilter serta evaluasi pengembangan model biofilm, pengendali reaksi dan konveksi-difusi-reaksi (KDR). Hasil pengujian menunjukkan efisiensi penyisihan gas H2S menggunakan kedua jenis media mencapai 99,5%, dan untuk kontaminan NH3 mencapai 99% pada media seraut sawit dan bervariasi pada selang 60-98% untuk media limbah padat karet. Dari pengembangan model menunjukkan bahwa profil laju penyisihan kontaminan dapat diprediksi dengan model biofilm dan model pembatas reaksi. Kinetika penyisihan tersebut dikendalikan oleh reaksi biokimia mikroorganisme pada biofilm. Model KDR dinilai cocok untuk memprediksi profil konsentrasi kontaminan sepanjang biofilter.   Kata kunci : biofiltrasi, biofilm, konveksi-difusi-reaksi, kinetika, media, model, H2S, NH

Recent progress in integrated fixed-film activated sludge process for wastewater treatment: a review

Integrated fixed-film activated sludge (IFAS) process is considered as one of the leading-edge processes that provides a sustainable solution for wastewater treatment. IFAS was introduced as an advancement of the moving bed biofilm reactor by integrating the attached and the suspended growth systems. IFAS offers advantages over the conventional activated sludge process such as reduced footprint, enhanced nutrient removal, complete nitrification, longer solids retention time and better removal of anthropogenic composites. IFAS has been recognized as an attractive option as stated from the results of many pilot and full scales studies. Generally, IFAS achieves >90% removals for combined chemical oxygen demand and ammonia, improves sludge settling properties and enhances operational stability. Recently developed IFAS reactors incorporate frameworks for either methane production, energy generation through algae, or microbial fuel cells. This review details the recent development in IFAS with the focus on the pilot and full-scale applications. The microbial community analyses of IFAS biofilm and floc are underlined along with the special emphasis on organics and nitrogen removals, as well as the future research perspectives

Finned spacer for enhancing the impact of air bubbles for membrane fouling control in chlorella vulgaris filtration

Membrane filtration offers appreciable promise as an effective process to harvest microalgae biomass but largely limited by membrane fouling. This study proposed a new spacer system for fouling control in Chlorella vulgaris filtration. Results demonstrate the effectiveness of finned spacer in directing the air bubbles toward the membrane surface thus improve their contacts and their foulant removal impacts. The projection of air bubbles is more effective at narrow fins gaps. The increasing aeration rate proportionally increases permeance until reaching a plateau value of 870 ± 11 L·m−2·h−1·bar at 1.5 L·min−1 aeration, the highest reported value so far. Switching mode can be applied to increase module packing density without compromising performance and is effective at switching periods of <5 min. Overall results are very encouraging and promising to obtain significant improvement in membrane fouling control

Novel activated carbon nanofibers composited with cost-effective graphene-based materials for enhanced adsorption performance toward methane

Various types of activated carbon nanofibers' (ACNFs) composites have been extensively studied and reported recently due to their extraordinary properties and applications. This study reports the fabrication and assessments of ACNFs incorporated with graphene-based materials, known as gACNFs, via simple electrospinning and subsequent physical activation process. TGA analysis proved graphene-derived rice husk ashes (GRHA)/ACNFs possess twice the carbon yield and thermally stable properties compared to other samples. Raman spectra, XRD, and FTIR analyses explained the chemical structures in all resultant gACNFs samples. The SEM and EDX results revealed the average fiber diameters of the gACNFs, ranging from 250 to 400 nm, and the successful incorporation of both GRHA and reduced graphene oxide (rGO) into the ACNFs' structures. The results revealed that ACNFs incorporated with GRHA possesses the highest specific surface area (SSA), of 384 m2/g, with high micropore volume, of 0.1580 cm3/g, which is up to 88% of the total pore volume. The GRHA/ACNF was found to be a better adsorbent for CH4 compared to pristine ACNFs and reduced graphene oxide (rGO/ACNF) as it showed sorption up to 66.40 mmol/g at 25 °C and 12 bar. The sorption capacity of the GRHA/ACNF was impressively higher than earlier reported studies on ACNFs and ACNF composites. Interestingly, the CH4 adsorption of all ACNF samples obeyed the pseudo-second-order kinetic model at low pressure (4 bar), indicating the chemisorption behaviors. However, it obeyed the pseudo-first order at higher pressures (8 and 12 bar), indicating the physisorption behaviors. These results correspond to the textural properties that describe that the high adsorption capacity of CH4 at high pressure is mainly dependent upon the specific surface area (SSA), pore size distribution, and the suitable range of pore size