Optimization of hollow fiber-supported liquid membrane operating parameters for levulinic acid separation: Modeling and experimental investigation

Hollow fiber-supported liquid membrane (HFSLM) is a highly promising technology for the separation of levulinic acid (LA), which is one of the leading biomass products. This process is particularly advantageous for industrial-scale applications due to its capability for continuous extraction and back extraction within a single operational device. This study employed HFSLM for the extraction of LA from an aqueous solution. To optimize HFSLM performance, response surface methodology with central composite face-centered (CCF) design was used to fine-tune three key factors: the concentration of trioctylamine (TOA) as a carrier, the concentration of sodium hydroxide (NaOH) as a stripping agent, and the concentration of LA in the feed solution. The ideal operating conditions for HFSLM were determined to be 0.32 M TOA, 0.77 M NaOH, and 10.08 g/L LA, resulting in the highest LA extraction efficiency of 74.82 % ± 3.83 %. The study also investigated the mass transfer mechanisms within the HFSLM system. Key parameters such as the extraction equilibrium constant (Kex), stripping equilibrium constant (Kst), distribution ratio (D), aqueous mass transfer coefficient (kf), and membrane mass transfer coefficient (km) were determined. The km value, measured at 5.1012 × 10−3 cm/s, exceeded the kf value of 0.6613 × 10−3 cm/s, indicating that the rate-limiting step in LA transport occurred during its diffusion through the film layer separating the feed and organic phases. A new mathematical diffusion flux model focusing on the extraction side of the liquid membrane system was developed to estimate the concentration of LA at different times. The model offers valuable insights into the transport mechanisms during LA extraction using HFSLM and can serve as a benchmark for integrating HFSLM into actual biomass processing

Effect of pore forming agents on the properties and performance of the supported liquid membrane for levulinic acid separation

The porosity of the membrane support plays a crucial role in the performance and efficiency of the supported liquid membrane (SLM) process. The formation of pores and the membrane porosity value can be improved by adding a pore-forming agent in the dope solution during membrane manufacturing. The objective of this study is to investigate the effect of pore-forming additives such as polyethyleneglycol (PEG) 200, PEG 20,000, lithium chloride, Tween-80, and polyvinyl pyrrolidone (PVP 10,000) on the polyethersulfone (PES) membrane properties and their performance in the separation of levulinic acid (LA) using the SLM method. The morphology, contact angle, porosity, and tensile strength of the membrane were evaluated. Among the pore-forming agents tested, PEG 200 emerged as the most effective in inducing a sponge-like structural wall in the PES membrane. It achieved a remarkable porosity level of 87.1%, displaying contact angles of 81.2° and 98° at the top and bottom surfaces, respectively, as well as a high tensile strength of 1032.88 kPa. The membrane achieved the highest extraction of 8.92 g/L LA in the SLM process using a 10 g/L LA aqueous feed solution

The use of factorial design for levulinic acid extraction via hollow fiber supported liquid membrane

Supported liquid membrane (SLM) is an effective method to separate a high-demand levulinic acid (LA) from an aqueous or biomass hydrolysate solution. Several factors can influence the separation of LA using SLM. In this study, three hollow fiber (HF) SLM (HFSLM) operation parameters, such as carrier concentration (0.1–0.5 M tri-n-octylamine, (TOA), stripping concentration (0.25–0.75 M sodium hydroxide (NaOH), and feed concentration (10–30 g/L LA) was analyzed by using a 23 full factorial design (FFD). The results showed that all three factors significantly impact the extraction of LA. The order of contribution effects towards LA extraction was LA feed concentration > NaOH stripping concentration > TOA carrier concentration. The design proposed a valid condition of factors such as 0.5 M TOA, 0.75 M NaOH, and 10 g/L of LA with LA extraction of 69.6 ± 2.16 %. The result proved that FFD effectively improved the LA extraction in the HFSLM process by considering all the factors involved

Performance of Forward Osmosis (FO) Membrane Fabricated from Different Molecular Weight of Polyvinylpyrrolidone (PVP) Additive

Despite of the emergence of revolutionary Forward Osmosis (FO) technology, the membrane is hindered by the severe effect of internal concentration polarization (ICP) which generated in membrane substrate layer. In current study, polyethersulfone (PES) membranes substrate layer were fabricated via phase inversion using three different polyvinylpyrrolidone (PVP; molecular weight of 10 kDa, 40 kDa and 360 kDa) which act as a pore former agent. Using 2 wt% of aqueous m-phenylenediamine (MPD) and 0.15 wt% of trimesoyl chloride (TMC) in hexane, the active polyamide layer was formed on the top surface of PES substrate via interfacial polymerization to produce thin film composite (TFC) FO membrane. The performance of TFC FO membranes were evaluated and three intrinsic parameters; A, B and S were determined by mathematical model. The results attained were compared to find the optimized PVP molecular weight for FO membranes with desired performance. It was observed that FO membrane prepared with molecular weight PVP of 40 kDa exhibited excellent performance with low ICP, thus reduce the replacement of draw solute in FO application

Influence of Polyethersulfone substrate properties on the performance of thin film composite forward osmosis membrane: Effect of additive concentration, polymer concentration and casting thickness

This research seeks to optimize the impact of substrate parameters such as polyvinylpyrrolidone (PVP) additive concentration (3–11 wt%), polyethersulfone (PES) concentration (11–17 wt%), and casting thickness (100–250 μm) on the overall performances of (PES) thin film composite (TFC) FO membrane. Non-solvent induced phase separation (NIPS) method was used to fabricate the substrate membrane, which was then followed by the interfacial polymerization of m-phenylene diamine (MPD) in aqueous solution and trimesoyl chloride (TMC) in hexane-organic solvent to form the active polyamide (PA) layer. Analyses of contact angle, porosity, pore size, functional group, morphology, and surface roughness were performed on membrane substrates and TFC membrane. Membrane performance parameters such as water flux (Jw), reverse salt diffusion (RSD), and specific reverse flux (SRF) were evaluated for the fabricated TFC membranes using the FO filtration system (pure water as feed solution and NaCl as draw solution). In addition, the water permeability coefficient (A), the solute permeability coefficient (B), and the structural parameter (S) were computed mathematically. Optimized membranes were chosen using the specific reverse flux (SRF) as the principal performance indicator. The optimal membranes for each parameter were then evaluated for their antifouling and rejection properties using humic acid (HA) solution. Among the optimized membranes, 15%PES/5%PVP/100 μm membrane exhibited the best performance with high rejection and antifouling properties towards HA

Tetrabutylphosphonium trifluoroacetate ([P4444]CF3 COO) thermoresponsive ionic liquid as a draw solution for forward osmosis process = Larutan ionik responsif haba tetrabutilfosfonium trifluoroasetat ([P4444]CF3 COO) sebagai larutan penarik untuk proses osmosis kehadapan

Forward osmosis (FO) is recognized as a potential membrane technology that utilizes low energy for water desalination. It is driven by natural osmotic pressure difference between feed solution and draw solution across semipermeable membrane. Pure water will permeate from the salinity feed water to the draw solution side. In order to produce pure water, it is necessary to find the best draw solute that exhibits high draw ability and can separate the permeated water efficiently from the draw solution. In the current study, lower critical solution temperature (LCST) thermoresponsive ionic liquid (IL) of tetrabutylphosphonium trifluoroacetate ([P4444]CF3COO) was synthesized as the draw solute for FO process. ([P4444]CF3COO) is dissolved in water below its critical temperature of 29°C and becomes two layered above this critical temperature. [P4444]CF3COO IL showed high water flux of 0.44 ± 0.007 LMH compared to the water flux of 0.32 ± 0.049 LMH for the NaCl draw solute at the same draw solution concentration. Applying thermoresponsive IL as the draw solute in FO process has the potential to treat high salinity of feed stream with ease of water recovery and draw solute regeneration

Recovery of xylose from oil palm frond (OPF) bagasse hydrolysate using commercial spiral-wound nanofiltration membrane

Oil palm fronds (OPF) is the most abundant agriculture wastes in Malaysia. This agriculture waste contains lignocellulosic materials that are potentially to be used as renewable material for production of value added products such as biosugar (i.e. xylose and glucose). Xylose is an intermediate product in xylitol production and glucose interferes in the process of separation. These two different types of monosaccharides can possibly be separated using NF membrane according to their molecular size rather than diffusivities. Thus, the aim of this study was to develop and evaluate the performance of pilot scale commercial spiral wound NF membranes (Desal-5 DK, Desal-5 DL and NF90) for separation of xylose from glucose. Using the synthetic sugar solution model, the Desal-5 DK membrane exhibited the highest xylose separation factor up to 1.17 at the operating pressure of 10 bar while the other two membranes were unable to separate the sugars (separation factor less than 1). For the recovery of xylose from the real oil palm frond (OPF) bagasse hydrolysate, the Desal-5 DK membrane perform very well with xylose separation factor of 1.63. Overall, it can be concluded that the spiral wound nanofiltration membrane offers cost-effective and easy-maintenance, which has high potential application in large scale separation of xylose-glucose from OPF bagasse hydrolysate

Influence of dope composition of polyethersulfone membrane blend with cellulose nanocrystal and carboxylated multi-walled carbon nanotube on humic acid rejection

A full factorial experimental design was employed to investigate the dope composition of a membrane made of cellulose nanocrystal (CNC), multi-walled carbon nanotube (MWCNT), and polyethersulfone (PES) for its ability to reject humic acid (HA). Four factors were screened, including PES composition, polyvinylpyrrolidone content, CNC content, and carboxylated MWCNT content. The membranes were tested for HA rejection using a 10-ppm aqueous feed solution. The results indicated that the percentage of MWCNT had the most significant impact, contributing 72.31% to the overall contribution. The fabricated membranes exhibited high HA removal capacity of up to 90% for the membrane embedded with MWCNT. The model's predicted values agreed reasonably with the experimental data, indicating the model's validity. This study provides insights into the development of CNC/MWCNT/PES membranes for efficient HA rejection in water treatment applications

Effect of methacrylic acid monomer on UV-grafted polyethersulfone forward osmosis membrane

UV irradiation is one of the procedures that has been considered for membrane surface graft polymerization. It is commonly utilized for enhancing the wettability of polyethersulfone (PES) membranes. In this research study, the monomer methacrylic acid (MAA) was used for the UV grafting process of a commercial NF2 PES membrane for the preparation of a forward osmosis (FO) membrane. Three different monomer concentrations and three different UV irradiation times were considered. The intrinsic characteristics of both the surface-modified and pristine membranes were determined via a non-pressurized test method. Compared to the NF2 PES, the surface of the modified membranes was rendered more hydrophilic, as the measured water contact angle was reduced considerably from 65° to 32–58°. The membrane surface modification was also confirmed by the data collected from other techniques, such as atomic force microscopy (AFM), field emission-scanning electron microscope (FESEM) and Fourier-transform infrared spectroscopy–attenuated total reflectance (FTIR–ATR). Additionally, the modified membranes exhibited a greater water permeate flux (Jw) compared to the NF2 PES membrane. In this study, the water permeability (A), solute permeability (B) and structural parameter (S) were determined via a two-stage FO non-pressurized test method, changing the membrane orientation. Compared to the FO pressurized test, smaller S values were obtained with significantly high A and B values for the two non-pressurized tests. The adopted method in the current study is more adequate for determining the intrinsic characteristics of FO membranes

STUDY OF DIFFERENT TREATMENT METHODS ON CHICKEN FEATHER BIOMASS

The chicken feathers (CFs)  consist of up to 10 % of total chicken dry mass and they have many potential industrial applications. CFs contains protein fibers named as keratin, which is an insoluble protein. Primary sanitization phases are complex because of the presence of lots of blood born microbes, pathogens and parasites in raw biomass. The extraction process of keratins from the unprocessed feathers is also a challenging task. Prior to the extraction cleaning/sanitization of feathers is a very necessary step. Thus, the present work was conducted to optimize  an efficient surfactant  for the cleaning process of the  CFs by using ionic and non-ionic surfactants. The experiment was conducted by the washing of feathers with double distilled water (ddH2O), detergents, ether and lastly with boiling water. The washed feathers treated with surfactants and the effect of each surfactant was analyzed by a microbiological test which tells about the extent of  the presence of different bacteria on the treated feathers. SEM, EDX, FTIR were used to study the morphology and composition of  untreated and treated CFs. SEM showed there was no detectable fiber damage after treatment. Cetrimonium bromide (CTAB) (t3) was one of the best surfactant for the treatment of CFs among all the surfactant used. The present study described the best treatment method  for the CFs.