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Researchers from Khulna College of Engineering and Know-how (KUET) have developed a 3D printed honeycomb filter made to deal with greywater from home sources.
The filter was produced on an Ultimaker FFF 3D printer, utilizing virgin nylon filament blended with recycled materials obtained by depolymerising discarded nylon cloth, then coated with titanium dioxide (TiO₂) nanoparticles. Nylon was chosen for its chemical resistance, power, and sturdiness beneath repeated publicity to wastewater, making it extra appropriate than different frequent 3D printing supplies reminiscent of PLA, ABS, or PETG.
Led by Sumit Kanti Saha from the Division of Textile Engineering, the challenge additionally noticed contributions from Jashore College of Science and Know-how. Revealed in Micro & Nano Letters, the work explores a low-cost, reusable possibility for non-potable water purposes. Whereas the outcomes are promising, the group notes that additional refinement is required earlier than the design might meet ingesting water requirements.
Greywater trials and efficiency outcomes
Measuring 195 × 195 mm with 5.44 mm hexagonal cells and 58% porosity, the honeycomb construction was designed to stability floor space, mechanical stability, and environment friendly fluid stream. Printing with recycled nylon posed challenges reminiscent of moisture absorption and slight filament diameter variations, which the group addressed by pre-drying the fabric and lowering print velocity.
After printing, the filter was coated with TiO₂ nanoparticles through spin coating, making a floor that inspired contaminants to cling and kind a dense cake layer early within the filtration course of.
In accordance with the group, checks have been carried out on greywater collected from residential services utilizing two filtration modes. In lifeless finish filtration, water flowed perpendicularly by the filter floor. Whereas in depth filtration, it handed by a dice of stacked honeycomb layers, trapping contaminants all through the construction.
Each configurations have been examined for 5 consecutive cycles with out cleansing. Within the first cycle, the TiO₂-coated filter in lifeless finish mode eliminated as much as 85% of biochemical oxygen demand (BOD) and 80% of chemical oxygen demand (COD). Depth filtration eliminated 80% BOD and 75% COD throughout the first cycle. By the fifth cycle, these charges had fallen to 62% BOD and 55% COD for lifeless finish, and 58% BOD and 50% COD for depth filtration.
Microscopy revealed heavier particle deposits on TiO₂-coated surfaces, whereas energy-dispersive X-ray spectroscopy confirmed the coating and detected larger carbon content material after use, signalling captured natural matter.
Regardless of these outcomes, turbidity and whole suspended solids (TSS) remained properly above Bangladesh’s ingesting water limits. After remedy, turbidity ranged between 235 and 247 NTU, far exceeding the ten NTU normal, and TSS stayed above 410 mg/L, in contrast with the allowable 10 mg/L.
The massive pores and open construction let finer particles cross by. Clogging patterns additionally differed: in lifeless finish mode, the stream fee dropped from 20 to 7 mL/min over 5 cycles, with strain rising from 5 to 35 Pa; in depth filtration, stream declined from 25 to 10 mL/min and strain elevated from 3 to 30 Pa.
The clogging index reached 0.65 for lifeless finish and 0.60 for depth filtration, prompting the authors to recommend upkeep choices reminiscent of backwashing or chemical rinsing to increase the filter’s lifespan.
Utilizing recycled nylon minimize materials prices by as much as 40%, bringing the fee per module to beneath $2 USD. Whereas 3D printing is slower than industrial manufacturing, it allows native manufacturing with out moulds, making it properly suited to small-batch and decentralised water remedy.
The researchers see this as a possible possibility for purposes reminiscent of irrigation, rest room flushing and cleansing. They advocate lowering pore dimension, including a number of layers or combining with finer filtration media to enhance turbidity and TSS elimination, and fine-tuning TiO₂ loading to stability sturdy preliminary efficiency with an extended working life.
3D printing boosts industrial water restoration
With rising calls for for sustainability, industries worldwide are beneath rising strain to seek out environment friendly methods to recycle water.
Excessive-performance ceramic 3D printers and supplies producer Lithoz and Evove collaborated to supply Separonics ceramic filter membranes for lithium extraction and industrial water recycling, utilizing the CeraFab S320 lithography-based ceramic manufacturing system. The LCM course of enabled tailor-made geometries, enhanced sturdiness, lowered tooling prices, and supported environment friendly large-scale manufacturing.
Comprised of sturdy alumina ceramic, the membranes have been constructed by stacking 20 exactly engineered segments, every 10 cm in diameter and 5 cm in peak, right into a 1 m filtration module with uniform pore dimension and distribution. This configuration delivered 5 instances larger output, diminished power use by 80%, and recovered 80% extra water than typical strategies.
Elsewhere, NTU-spin off Nano Solar launched a 3D printing facility in Tuas to supply water filtration membranes. Created in a single printing step, the membranes have been reported to be 5 instances extra environment friendly than typical polymer or ceramic-based choices.
The plant can produce as much as 600 m² of membranes per day for sectors together with semiconductor manufacturing and wastewater remedy. Developed beneath the steering of NTU Affiliate Professor Darren Solar, the know-how makes use of wonderful strands to seize pollution whereas lowering house, labor, and useful resource wants. On the time of reporting, the $6 million facility had already secured contracts for makes use of reminiscent of wastewater remedy, kidney dialysis, and potential purposes in artificial pores and skin manufacturing.
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Featured picture reveals the dead-end filtration approach. Picture through KUET.
