New low-cost nylon 3D printed filter analysis removes as much as 85% of greywater pollution

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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 material, then coated with titanium dioxide (TiO₂) nanoparticles. Nylon was chosen for its chemical resistance, energy, and sturdiness beneath repeated publicity to wastewater, making it extra appropriate than different widespread 3D printing supplies reminiscent of PLA, ABS, or PETG.

Led by Sumit Kanti Saha from the Division of Textile Engineering, the venture additionally noticed contributions from Jashore College of Science and Know-how. Printed in Micro & Nano Letters, the work explores a low-cost, reusable possibility for non-potable water functions. Whereas the outcomes are promising, the workforce notes that additional refinement is required earlier than the design may 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 workforce addressed by pre-drying the fabric and lowering print pace.

After printing, the filter was coated with TiO₂ nanoparticles through spin coating, making a floor that inspired contaminants to cling and type a dense cake layer early within the filtration course of.

In line with the workforce, exams had been carried out on greywater collected from residential amenities utilizing two filtration modes. In lifeless finish filtration, water flowed perpendicularly by means of the filter floor. Whereas in depth filtration, it handed by means of a dice of stacked honeycomb layers, trapping contaminants all through the construction. 

Each configurations had 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 in the course of 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 complete suspended solids (TSS) remained nicely above Bangladesh’s ingesting water limits. After remedy, turbidity ranged between 235 and 247 NTU, far exceeding the ten NTU customary, and TSS stayed above 410 mg/L, in contrast with the allowable 10 mg/L. 

The big pores and open construction let finer particles cross by means of. Clogging patterns additionally differed: in lifeless finish mode, the stream charge dropped from 20 to 7 mL/min over 5 cycles, with stress rising from 5 to 35 Pa; in depth filtration, stream declined from 25 to 10 mL/min and stress 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 counsel upkeep choices reminiscent of backwashing or chemical rinsing to increase the filter’s lifespan.

Utilizing recycled nylon reduce 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 permits native manufacturing with out moulds, making it nicely suited to small-batch and decentralised water remedy. 

The researchers see this as a possible possibility for functions reminiscent of irrigation, bathroom 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 stress to seek out environment friendly methods to recycle water.

Excessive-performance ceramic 3D printers and supplies producer Lithoz and Evove collaborated to provide 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.

Produced from sturdy alumina ceramic, the membranes had 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 occasions larger output, decreased power use by 80%, and recovered 80% extra water than standard strategies. 

Elsewhere, NTU-spin off Nano Solar launched a 3D printing facility in Tuas to provide water filtration membranes. Created in a single printing step, the membranes had been reported to be 5 occasions extra environment friendly than standard 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 expertise makes use of high-quality 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 functions in artificial pores and skin manufacturing.

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Featured picture reveals the dead-end filtration approach. Picture through KUET.