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

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

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

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

Gradual PVP leaching from PVDF/PVP blend membranes and its effects on membrane fouling in membrane bioreactors

© 2018 Elsevier B.V. Improving the hydrodynamics on the membrane surface in a magnetically induced membrane vibration system (MMV) has been proven efficient for membrane fouling control in membrane bioreactors. This advantage can be further extended by using an optimized membrane. This was realized in this study by preparing porous polyvinylidene fluoride membranes via polyvinylpyrrolidone (PVP) blending and later by leaching out the PVP from the membrane matrix via post-treatment using NaOCl. Results show that increasing the PVP content in the casting solution increases membrane fouling resistance. Slowly leaching of PVP after several periodic NaOCl cleanings increased membrane permeance. No advantage of NaOCl post-treatment was observed. The long-term filtration confirmed the superiority of the highly porous membrane that complemented the advantages offered by the MMV system. This suggests that despite the small quantity of the remaining PVP, its leaching offered a substantial gain to improve membrane filterability.status: publishe

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

New Concept for Dual-Layer Hydrophilic/Hydrophobic Composite Membrane for Membrane Distillation

This study presents a new concept of a simple method for the synthesis of dual layer hydrophilic/hydrophobic composite membranes for membrane distillation (MD). The membranes were prepared of poly(vinylidenefluoride) (PVDF) by phase inversion. The synthesis was realized by allowing a full or partial penetration of the polymer solution through one or two non-woven support (NWS) layers. This was achieved by proper selection of a thin NWS having high stiffness, high porosity and low surface tension, in combination with a runny polymer solution and sufficient time gap between casting and coagulation. The applied preparation method was effective in yielding dual layer composite membranes. The first layer atop the NWS was a hydrophilic or slightly hydrophobic one (contact angle (CA) of 88-92º), while the bottom layer beneath the NWS was highly hydrophobic (CA=132-140º). The difference in surface energy between the top and bottom layers originated from a difference in morphology. A smooth and dense top layer is formed as a result of an instantaneous demixing, while a porous and multi-scale network with some degrees of spherulitical structure was formed on the bottom by a delayed demixing mechanism. Direct contact MD (DCMD) results showed that the obtained flux was comparable to other composite MD membranes with high salt rejection. Membrane alignment inside the MD module is a critical element in determining the membrane performance and is shown to significantly increase flux when a top facing feed configuration is used

Decreasing membrane fouling during Chlorella vulgaris broth filtration via membrane development and coagulant assisted filtration

© 2015 Elsevier B.V. Membrane filtration has been reported as an interesting low-cost technique for microalgae harvesting, either in a separated process or in a coupled process as in a membrane photobioreactor. However, the filtration performance can still be improved if the membrane fouling problem could be properly managed. In this study, the improvement of the filterability of a Chlorella vulgaris broth is investigated via both membrane development and via coagulant dosing before filtration. For the membrane development (via the process of phase inversion), four basic membrane preparation parameters were studied, namely polymer concentration, time gap between casting and coagulation, addition of water as a non-solvent into the casting dope solution and the addition of polyvinylpyrrolidone as an additive to a polyvinylidene fluoride/N,N-dimethylformamide system. For coagulation, FeCl3 and chitosan were tested using a polycarbonate 0.1μm membrane. Later, three new membranes were tested against two commercial membranes with and without coagulant dosing. The performance of the membrane was evaluated using the improved flux stepping filtration method and using a simple dead-end filtration for the coagulation/filtration study, respectively. Results show that the membrane properties and the filterability could be well manipulated by using the four phase inversion parameters. Both coagulants increased the filterability of the broth. When applied to the optimized membranes and the two commercial membranes, dosing 10ppm chitosan in the C. vulgaris broth had inconclusive effects. It improved filterability for most of them but imposed negative effect for the rest, which suggests that the coagulant type and dosing of a membrane filtration system should be optimized per membrane.status: publishe