Key Engineering Materials Vol. 1052

Abstract: As freshwater availability has progressively decreased, this study presents a 3D-printed module housing system designed for solar-powered passive desalination and water production. To evaluate its performance, the module was tested in a controlled laboratory setting under one sun illumination. Under a salinity level of 3.5%, the design achieved an evaporation rate of 0.1458 kg/m²hr and a condensation rate of 0.0623 kg/m²hr, yielding a total of 20.13 g of desalinated water. The condensation efficiency was 42.7%, and the collected water had a salinity of 0.63%, highlighting opportunities for optimization in small-scale solar desalination. While these results indicate strong potential, further evaluation of the 3D-printed module housing will be conducted to assess its long-term durability, drinking water quality, and performance under outdoor conditions. With its modular design, efficient operation, and 3D-printed structure, this system holds promise as a scalable and sustainable solution for water-scarce communities worldwide.

Abstract: Adoption of desalination technologies to produce fresh water in developing countries remains underutilized due to the substantial energy consumption, high operational costs, and membrane fouling associated with conventional methods. Microbial desalination cells (MDCs) have emerged as a promising alternative, offering simultaneous wastewater treatment, bioelectricity generation, and salt removal. This study aimed to evaluate the bio-templating of copper and zinc oxide nanoparticles on waste-derived eggshell membranes (CZ-ESM) and subsequently incorporated into ion exchange membranes (IEMs) for MDC applications. Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS) confirmed the presence of calcinated CZ-ESM in the IEMs. The modified and control IEMs were compared based on water uptake, mechanical strength, biofouling resistance, and salt removal. Incorporation of calcinated CZ-ESM nanocomposites enhanced membrane hydrophilicity, reflected in increased water uptake while also exhibiting reduced microbial colonization, thereby improving anti-fouling performance. However, the addition of calcinated CZ-ESM nanocomposites resulted in decreased tensile strength due to nanocomposite aggregation and heterogeneous resin distribution. Modification of the IEMs showed statistically the same salt removal as that of the unmodified counterpart. These findings demonstrate the use of CZ-ESM nanocomposites as fillers for MDC membranes, highlighting their ability to enhance hydrophilicity and antifouling properties, but improvements in the mechanical properties and salt removal must be further investigated to address practical limitations in the MDC application.

Abstract: The increasing demand for clean water necessitates the development of advanced and cost-effective treatment technologies. Nanofiltration (NF) membranes offer high efficiency in removing divalent ions, but their application is often limited by membrane fouling and stability issues. While various polymer blends have been studied to address these limitations, the effect of incorporating chitosan (CS) into polyethylene glycol/cellulose acetate (PEG/CA) membranes for treating calcium-rich water remains underexplored. This study aimed to evaluate the impact of CS incorporation on the performance of PEG/CA NF membranes, specifically focusing on water flux and salt rejection in the removal of calcium carbonate from simulated groundwater. Membranes with 1–3 wt % CS were fabricated and compared to unmodified PEG/CA membranes. Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy confirmed CS presence, while Scanning Electron Microscopy (SEM) revealed morphological changes. Performance testing showed that the 1 % CS membrane had the highest water flux, whereas the 3 % CS membrane achieved the highest salt rejection. An inverse relationship between flux and rejection was observed with increasing CS content. Statistical analysis confirmed significant performance differences between modified and unmodified membranes. These results indicate that chitosan incorporation enhances NF membrane performance, offering a promising approach for improving water purification systems, particularly for hard water treatment.

Abstract: Wastewater of domestic kitchen (KWW) may contain significant quantity of cooking oil residues and form problem of blocking domestic sewage pipe as cooking oil accumulated and clump inside the sewage pipe requiring cleaning and process for the removal of clumped oil residues. This study was designed to examine the efficiency of synthetic filter consisting of walnut shells in the removal of cooking oil residues from kitchen wastewater in addition to improve other wastewater variables such as pH, electric conductivity and total dissolved solids. where all collected kitchen wastewater samples were examined during November 2024 in Technical College of Al-Musaib lap. The synthetic filter was prepared by using a polyethylene plastic tube with 30 cm length and 10 cm diameter giving a volume of 2336.5 cm3. This tube had two ends where the upper end for receiving kitchen wastewater while the lower end for the draining. About 150 g of walnut shells with various sizes were placed in the synthetic filter where the upper end was linked to the pipe of kitchen sink while the lower end was connected to draining plastic container in order to examine the wastewater containing cooking oil residues. This study was proceeded at lab scale and the examination was carried out firstly via filtering wastewater using only Whatman filter paper to act as control and secondly via synthetic filter containing walnut shells which was repeated three times. A total of 2000 cm3 domestic kitchen wastewater was obtained and divided into 4 subsamples of 250 cm3 each where the sample was used for control test while the remaining 3 subsamples used for walnut shells filter. The obtained results have shown that mean pH value of control sample was 9.1 ± 0.2 while it was almost similar for the walnut shells filter samples and varied from 7.5 ± 0.2 to 7.6 ± 0.1. For wastewater electric conductivity electric conductivity ( EC), it was found that control sample had higher mean value of 3192.5 ± 317.7 µs/cm and the walnut shell filter samples have had lower mean values varying from 2425.3 ± 295.0 µs/cm to 2754.4 ± 44.55 µs/cm. Regarding wastewater total dissolved solid (TDS) content, it was recorded that control sample had much higher mean value (3072.67 ± 47.5 ppm) than those of walnut shells samples which ranged from minimum value of 1381.0 ±13.0 to maximum value of 1414.0 ± 74.0 ppm. In case of cooking oil residues, the study has recorded significantly higher mean value of 7.3 ± 0.8 gm in control wastewater sample while walnut sells filtered samples had much lower mean values varying from 2.94 ± 0.08 to 3.3 ±0.2 gm. It seems very clearly that walnut shell filter has removed significant quantity (Probability ≤ 0.05) of cooking oil residues from the kitchen wastewater.

Abstract: Bottled drinking water is widely consumed, yet its quality can be compromised by improper storage conditions, such as heat and direct sunlight. This study investigated the impact of environmental conditions on five bottled water brands prevalent in Babylon Governorate. Samples were preserved under three conditions: ambient room temperature, constant sunlight exposure, and heating at 55 °C. Essential quality measures, including as pH, total dissolved solids (TDS), hardness, conductivity, and turbidity, were examined. The results indicated that heat exposure resulted in the most pronounced alterations, with TDS escalating to 163, hardness attaining 16.3 , and conductivity significantly increasing across several brands. Exposure to sunlight caused mild fluctuations, especially in pH and mineral solubility, whereas samples stored under standard conditions exhibited stability.Despite the fact that every tested value was under WHO safety guidelines, the findings show that extended exposure may cause progressive chemical changes. A low-cost monitoring device was created utilizing pH, TDS, turbidity, and temperature sensors, linked with NodeMCU and ThingSpeak for real-time data transmission and storage. This device provides a practical tool for ensuring water safety in households, laboratories, and medical settings.

Abstract: The findings from this study proved the possible usefulness of shredded recycled rubbers from scrap tires as a cheap and effective method for eliminating nitrate ions from water, especially within a certain pH range. Maximum adsorption efficiency was found to occur around pH = 6 which suggested that the surface charge on the adsorbent and the concentration of ions in the medium observed were critical for adsorption. Under controlled conditions and a pH of 6 with an original concentration of 100 mg/L, the adsorption efficiencies of NaNO₃ and KNO₃ were 67% and 60% respectively. These increased to 77% and 70% at 200 mg/L, pH 6. These results elucidate that the type of cation and the chemistry of the solution influences the adsorption process. The kind of nitrate salt employed also had an impact on removal efficiency, with potassium nitrate performing better than sodium nitrate, highlighting the relevance of the associated cation type in the process. As a result, the utilization of recycled rubber might be regarded as an environmentally viable solution for treating nitrate-contaminated water, especially in decentralized treatment systems and mild pH conditions. In addition, shredded tire rubber provides an effective, low-cost, and sustainable solution for nitrate-contaminated groundwater treatment.

Abstract: This study investigates the effect of contact time on the phytoremediation efficiency of Fittonia argyroneura and Syngonium podophyllum in treating synthetic domestic wastewater. The performance of both plant species was evaluated over a contact time range of 24 to 120 hours by monitoring the removal efficiency of key pollutants, including nitrate (NO₃⁻), phosphate (PO₄³⁻), biochemical oxygen demand (BOD), and chemical oxygen demand (COD). Results revealed that both species demonstrated a significant capacity for contaminant removal, albeit with varying effectiveness. Syngonium podophyllum showed superior performance in nutrient removal, achieving maximum removal efficiencies approximately of 100% for nitrate and 60% for phosphate at 24 and 120 hours, respectively. In terms of biological oxygen demand (BOD), Fittonia argyroneura had a maximum removal rate of almost 90% at a contact period 120 hr., whereas Syngonium podophyllum had a removal rate of 70% at a contact time of 72 hours. Fittonia argyroneura and Syngonium podophyllum plants had the highest COD elimination rates after a 120-hour contact period, at 85% and 79%, respectively. F. argyroneura also stimulates the establishment of aerobic bacterial populations, which play a key role in the oxidation and degradation of organic compounds. The results obtained emphasize the potential of ornamental plants for phytoremediation of wastewater, with distinct species exhibiting preferential removal of specific pollutants dependent on contact time.