Algae Removal Research Articles

A multi-dimensional comparative study on the performance of algae removal using various flotation

Flotation is considered the most cost-effective and efficient algae-water separation technology. However, there are various flotation techniques for algae removal, such as coagulation-flotation (CF), foam flotation (FF), and positively charged bubble flotation (PF). It remains unclear which method is most suitable for removing algae from water bodies and under what specific conditions each technique is most effective. This study systematically compares CF, FF, and PF in terms of algal cell removal efficiency, concentration ratio, flotation kinetics, impact on algal cells, removal efficiency of algal organic matter (AOM) and microcystins (MC-LR), as well as economic cost analysis. CF is better suited for algae removal in water bodies, including drinking water sources, using fixed installations on shore due to its high removal efficiency, high concentration ratio, low chemical dosage, and minimal residuals. FF is more appropriate for non-drinking water sources as it can remove algae and further control algal growth; however, its residual CTAB may pose a threat to drinking water safety. PF is most suitable for in situ algae removal within water bodies, primarily because it does not require stirring or coagulation. Instead, modified bubbles can be directly introduced into the algal distribution layer, where they adhere to algal cells, facilitating algae-water separation. All three flotation methods are economically feasible for algae removal. For FF, the costs of chemicals and electricity are nearly equal, while for CF and PF, the primary cost is electricity. This study provides data to support the selection of appropriate flotation technologies for emergency removal of algal blooms in water bodies.

Behaviour of M. aeruginosa–Microplastic composite pollutants in coagulation and sludge storage

Microcystis aeruginosa (M. aeruginosa) blooms and microplastics pollution have been major global water pollution concern in lakes and reservoirs. In this study, the behaviour of M. aeruginosa–microplastic composite pollutants in inorganic coagulant (PACl) and organic coagulant (HTCC) treatment was investigated. Results showed that, in coagulation stage, the dissolved extracellular polymers secreted by M. aeruginosa could promote the adhesion of microplastics to algae, so as to combine them into the algal flocs, thus improving the sedimentation and removal efficiency of microplastics. On the other hand, whilst microplastics increased the size of algal flocs in PACl coagulation and improved algal removal efficiency, they had the opposite effect on HTCC coagulation. And the removal of algal metabolites including microcystins were improved by the presence of microplastics.In sludge storage stage, the oxidative and mechanical damage effects of microplastics promoted the rupture of M. aeruginosa cells in PACl sludge but not in HTCC sludge, which mean more potential risks in recycling of PACl sludge water. Besides, microplastics promoted the proliferation of beneficial bacteria such as Poterioochromonas and Coccomyxa, which contributed to the control of sludge pollution.

Individual and combined effects of sodium dichloroisocyanurate and isothiazolinone on the cyanobacteria-Vallisneria natans-microbe aquatic ecosystem

The use of algaecides to control high-density cyanobacterial blooms is often complicated by secondary pollution and the toxicity to non-target organisms. This study investigates the individual and combined effects of sodium dichloroisocyanurate (NaDCC, 5, 50, and 100 mg/L) and isothiazolinone (0.1, 0.5, and 1.5 mg/L) on a cyanobacteria-Vallisneria natans-microbe aquatic ecosystem, focusing on their interactions and ecological impacts. Results indicate that NaDCC could achieve a higher algae removal rate than isothiazolinone within 15 days, but has a greater negative effect on Vallisneria natans. Both algaecides disrupt nutrient and secondary metabolite balances at low and high concentrations, increasing nutrient loads and harmful substances. Optimal results were obtained with low concentrations of NaDCC (5 mg/L) and isothiazolinone (0.1 mg/L), effectively controlling cyanobacteria while minimizing harm to Vallisneria natans and reducing nutrient loads and microcystin accumulation. Algaecide application enhanced microbial diversity in water and leaves, shifting the dominant community from cyanobacteria to organisms adapted to the post-cyanobacterial decay environment. Metabolomic analysis indicated increased secretion of lipids and organic acids by cyanobacteria in response to algaecide stress. High concentrations of NaDCC and isothiazolinone disrupted nitrogen metabolism in cyanobacteria and induced ROS overproduction, affecting unsaturated fatty acid synthesis and other metabolic pathways. These findings highlight the importance of exploring different combinations of algaecides to reduce their concentrations, balance algal control with ecological stability, and offer insights for effective eutrophication management.

Exploring non-thermal plasma technology for microalgae removal

The global population and economic development surge has substantially increased water demand, resulting in heightened sewage and pollutant generation, posing environmental hazards. Addressing this challenge necessitates the implementation of efficient and cost-effective water reclamation methods. Non-thermal plasma technology (NTP) has emerged as a promising solution, garnering attention for its superior efficiency compared to alternatives. While existing studies have predominantly focused on energy efficiency and pollutant removal, limited research has delved into the biological removal aspect, particularly concerning algae. This study utilized a dielectric barrier plasma diffuser to eliminate Spirulina microalgae (Spirulina platensis) from wastewater solutions, demonstrating higher algae removal and superior mass transfer compared to alternative plasma methods. The effect of sample volume, input voltage and power, flow rate, and initial solution concentration on the algae removal was investigated. Investigation of operational parameters revealed the best condition resulting in a 98 % removal rate and 20 g/kWh energy efficiency. The best conditions for the removal of Spirulina microalgae were considered in a sample volume of 50 mL, a voltage of 7.6 kV, a flow rate of 700 mL/min, and an initial solution concentration of 1280 mg/liter. Scanning Electron Microscope (SEM) images illustrated the impact of active species on cell structure, leading to the destruction of spiral form and loss of reproductive ability. The study underscores the potential of NTP for efficient algae removal and identifies key active species involved in the process. The removal of Spirulina microalgae was attributed to a combination of singlet oxygen (1O2), hydroxyl radicals, and ozone.

Evaluation of ten plant-derived biocides for the inhibition of photosynthetic organisms on the karst surfaces of heritage buildings

Biodeterioration is a significant problem in the conservation of stone heritage buildings. In this study, 10 plant essential oils were assessed for their effectiveness in biofilm inhibition on stone heritage building surfaces under laboratory and in situ conditions, and were compared with traditional biocides such as benzalkonium chloride. The plant extracts were tested against algae and mosses. The effect on algae removal was evaluated by measuring the color of the surface before treatment, after 24 h and after 1 month of treatment. The effect on mosses was assessed by measuring the photosynthetic pigment content of mosses after 24 h of treatment. The results showed that the different plant extracts exhibited different levels of antibiotic activity. Benzalkonium chloride, S. aromaticum and C. cassia extracts showed strong antibiotic activity against all algae and mosses tested. T. mongolicus extracts showed antibiotic activity against only some of the algae and mosses, while the application of P. cablin extracts increased chlorophyll b content in the mosses. The other plant extracts were less effective at inhibiting the growth of algae and mosses. GC–MS compositional analysis further indicated that the higher antibiotic activity of S. aromaticum and C. cassia extracts was related to the high content of eugenol and cinnamaldehyde.

A novel lanthanum-modified polytitanium chloride coagulant: Efficient algae removal and enhanced photocatalytic ability of recycled algal sludge

The removal of harmful cyanobacterial blooms (HCBs) and reuse of the resulting algal sludge are pressing issues in current environmental governance and ecological conservation. Aiming at tackling the above-mentioned challenges, titanium (Ti)-based coagulants are promising candidates. However, most of them suffer from poor stability and weak actual algal removal ability, and recycling of the algal sludge usually produces titanium dioxide (TiO2) with low photocatalytic ability. In this work, a lanthanum (La)-modified polytitanium chloride (La-PTC) coagulant is reported. La in the La-PTC coagulant serves a "kill two birds with one stone" strategy in algae removal and algae sludge reuse. Owing to the introduction of La ions, the La-PTC coagulant exhibits ultra-high stability and excellent algae removal capability with an efficiency of 98.71%, which is 7.25% higher than that of PTC coagulant. Moreover, recycling algae sludge can prepare high catalytic (2.45 times the commercial P25 TiO2) La/C-TiO2, where the presence of La enhances its visible light response range and inhibits electron hole recombination. The strategy of this La modified coagulant can not only achieve efficient removal of HCBs, but also transform the recovered algal sludge into photocatalysts with higher catalytic capacity.

An efficient polyaluminum lanthanum silicate coagulant for phosphorus removal and algal bloom control

Due to the advantages of convenient operation and low cost, the use of coagulants is considered a promising method for algae bloom harvesting. However, large dosages, poor algal bloom control rates, and limited phosphorus removal efficiency restrict the usage of most coagulants. In this study, a novel polyaluminum lanthanum silicate (PALS) coagulant was used to remove phosphorus and control algal bloom. The results of isotherm study showed that phosphorus adsorption on PALS fitted Freundlich model, indicating chemisorption and heterogeneous multilayer adsorption were the mechanisms of phosphorus adsorption by PALS. The maximum phosphorus adsorption capacity of PALS by Langmuir model was 485.30mg/g. According to the algal bloom control experiments, the removal of algae and phosphorus was slight at low dosages of PALS (2mg/L and 5mg/L). Short-term control of the algal bloom was observed within 2 days in PALS-10 group, but the bloom recovered afterward, while phosphorus and algae were almost completely removed in PALS-15 and PALS-20. When the dosage of PALS was ≤ 10mg/L, PALS coated the algal cell surfaces and induced mild oxidative stress, showing a little damage to cell integrity. However, the PALS dose over 15mg/L could effectively capture algal cells through charge neutralization, cause severe oxidative stress, strongly upregulate the expression of selected five genes, significantly damage cell integrity, and lead to algae lysis. These findings demonstrated that PALS is a promising coagulant for phosphorus removal and algal bloom control in eutrophic waters, and the minimum threshold of its usage was 15mg/L.

Open-slit circular tube piezoelectric ultrasonic transducer with longitudinal bending mode conversion

Abstract A new type of longitudinal bending mode conversion ultrasonic transducer is designed by compounding a sandwich type piezoelectric ultrasonic transducer, amplitude transformer and Open-slit circular tube radiator. The radiator is made of a circular tube cut into a number of curved plates along the axis, and the two ends are thin disc end caps. The electromechanical equivalent circuit model of the transducer is established and its frequency equation is derived. The vibration performance of the transducer is studied by using the equivalent circuit method and the finite element method. The results show that: the new structure design and the longitudinal vibration sandwich piezoelectric ultrasonic transducer can effectively stimulate the two ends of the slit circular tube radiator to produce first-order bending vibration, and the curved plate to produce high-order bending vibration, so as to achieve high efficiency, uniform and all-round ultrasonic radiation. The research results are expected to be applied in ultrasonic treatment of large volume liquid such as ultrasonic wastewater treatment, ultrasonic algae removal and ultrasonic chemical reaction.

Advanced electrochemical strategies for simultaneous removal of Microcystis aeruginosa and microcystin-LR: On-demand optimization and mechanistic insights

The frequent occurrence of harmful cyanobacterial blooms and toxins poses significant threats to aquatic life and drinking water safety. This work reports the removal mechanisms of M. aeruginosa and microcystin-LR (MC-LR) using the Pt-Graphite felt (GF) electrochemical system, which builds upon prior research to investigate diverse processes driven by distinct mechanisms within a single reactor, primarily by pH regulation. Factors affecting removal were assessed through single-factor trials and Box-Behnken design, identifying optimal conditions for successful algae removal, finally a 96% removal efficiency of algae cells and an 83% elimination efficiency of MC-LR within a 60-minute timeframe. Particularly at non-optimal pH 7 conditions, the Pt-GF system showcases synergistic effects, enhancing electro-flocculation and weakening electro-Fenton reactions. Conversely, at an optimal pH of 3, the electro-Fenton process is favorably enhanced, leading to improved removal efficiency through escalated reactive oxygen species generation. Additionally, the system exhibits consistent repeatability in its performance. Notably, its effectiveness is substantiated across varying nitrogen and phosphorus levels and in simulated water samples containing multiple algal species. In essence, this subtly adaptable reactor tuning integrates electro-Fenton, electro-flocculation, electro-adsorption, and electrochemical direct oxidation effects for the first time, potentially providing a more effective and manageable solution for addressing harmful algae in water.

Conservation of stone heritage buildings: Exploring the algicidal properties of biologically-synthesized nano-silver

The degradation of stone heritage buildings by pioneer plants such as algae is a major challenge in heritage conservation research worldwide. At present, there is a lack of effective algaecides to inhibit the growth of algae on stone structures, prompting an urgent need to explore effective green methods to remove algae colonizing on surfaces of stone heritage buildings. Therefore, we explored the use of aqueous and alcoholic extracts of four plant leaves (Cinnamomum cassia leaf, Syzygium aromaticum leaf, Thymus mongolicus leaf and Pogostemon cablin leaf) to prepare silver nanoparticles. By optimizing the synthetic parameters, we optimized the yield of the nanoparticles and examined their algicidal activities through in-vitro and in-situ experiments. The experimental results showed that the chlorophyll-a concentrations of algae treated with nano-silver synthesized from the alcoholic extract of Cinnamomum cassia leaf decreased approximately threefold, and the algae removal rate reached 71.34%. Meanwhile, nano-silver treatment made the color of the stone chips colonized with algae close to the color of the uncolonized algae, which demonstrated that the nano-silver can effectively remove the algae colonized on the stone chips. This study confirms that nano-silver synthesized from plant leaves offer a viable strategy as a ‘green’ algaecide for stone heritage buildings.

Low-frequency ultrasound assisted contact-electro-catalysis for efficient inactivation of Microcystis aeruginosa

Frequent cyanobacterial blooms pose a serious threat to the aquatic ecosystem and human health, so developing an efficient algae removal method is a long-term goal for bloom management. Current technologies for algal bloom control need urgent improvement in terms of algicide recovery, eco-friendliness and cost. Here we propose a contact-electro-catalytic method, using polytetrafluoroethylene (PTFE) film as a reusable catalyst. This contact-electro-catalytic approach involves the generation of reactive oxygen species (e.g., O2•–, HO•, 1O2 and H2O2) through water-PTFE contact electrification under the low-frequency ultrasonic waves, facilitating the inactivation of algae. The removal rate of the cyanobacterium Microcystis aeruginosa (M. aeruginosa) exposured to the water-PTFE contact-electro-catalytic system is almost five times greater than that of ultrasound alone after 5 h. A mechanistic investigation revealed that the contact-electro-catalytic system damaged the photosynthetic activity, antioxidant system and membrane integrity of the cells. Additionally, LC-MS metabolomic analysis indicated that this system caused substantial significant disruptions in the TCA cycle, amino acid metabolism, purine metabolism and phospholipid metabolism. Three-dimensional fluorescence spectroscopy suggested contact-electro-catalysis could further availably degrade the organic matter. We anticipate that this method can provide an eco-friendly, highly efficient and economic approach for effective control of harmful algal blooms.

Effects of Irrigation with Slightly Algae-Contaminated Water on Soil Moisture, Nutrient Redistribution, and Microbial Community

The presence of excessive algae in water is always considered as a negative factor in irrigation. However, the optimal balance between algal removal and retention in irrigation water when the algal biomass is controllable remains unknown. Therefore, this study explores the impact of low-level algal presence (Scytonema javanicum) on soil and microbial activity through controlled soil column experiments. Soil moisture was measured, and 16S rRNA gene amplicons sequencing was applied to characterize the microbial community. Slight community changes indicated no negative impact on the local microbial community of S. javanicum. Enzyme assays and quantitative polymerase chain reaction (qPCR) revealed that algae improved soil moisture retention, and enhanced the nutrient content of the topsoil. The decrease in moisture in the treatment group (from 27.53% to 26.42%) was significantly reduced (p < 0.05) compared to the control (from 27.55% to 25.17%), while the contents of ammonium (NH3-N) and total nitrogen (TN) in the treatment (0.70 mg/kg and 0.54 g/kg) were also higher (p < 0.05) than that of the control (0.43 mg/kg and 0.49 g/kg). The results of the abundance of functional gene suggested algae facilitated nitrogen fixation and nitrification. This research offers innovative insights for diversifying the sources of irrigation water.

Emergency control of dinoflagellate bloom in freshwater with chlorine enhanced by solar radiation: Efficiency and mechanism

Dinoflagellate requires a lower temperature and blooms frequently in the spring and autumn compared to regular cyanobacteria. The outbreak of dinoflagellate bloom will also lead to the death of some aquatic organisms. However, research on freshwater dinoflagellates is still lacking due to the challenges posed by classification and culture in laboratory. The removal effect and mechanism of Peridinium umbonatum (P. umbonatum, a typical dinoflagellate) were investigated using solar/chlorine in this study. The effect of simulated solar alone on the removal of algae was negligible, and chlorine alone had only a slight effect in removing algae. However, solar/chlorine showed a better removal efficiency with shoulder length reduction factor and kmax enhancement factor of 2.80 and 3.8, respectively, indicating a shorter latency period and faster inactivation rate for solar/chlorine compared to solar and chlorine alone. The removal efficiency of algae gradually increased with the chlorine dosage, but it dropped as the cell density grew. When the experimental temperature was raised to 30 °C, algal removal efficiency significantly increased, as the temperature was unsuitable for the survival of P. umbonatum. Attacks on cell membranes by chlorine and hydroxyl radicals (•OH) produced by solar/chlorine led to a decrease in cell membrane integrity, leading to a rise in intracellular reactive oxygen species and an inhibition of photosynthetic and antioxidant systems. Cell regeneration was not observed in either the chlorine or solar/chlorine systems due to severe cell damage or cysts formation. In addition, natural solar radiation was demonstrated to have the same enhancing effect as simulated solar radiation. However, the algal removal efficiency of solar/chlorine in real water was reduced compared to 119 medium, mainly due to background material in the real water substrate that consumed the oxidant or acted as shading agents.

Controlling algal growth using ultrasonic technology and conceptual implementation in the real-life system

ABSTRACT The present work reports a study on the interactive response of algae and other microorganisms coexisting in a natural water body to ultrasonic treatment for effective algal growth inhibition using ultrasonic treatments. The cellular damage caused by treatment was also visualised through SEM imaging. For an ultrasonic exposure of 10–30 min at 30 kHz frequency with ultrasonic power dissipated in the range of 4.2–12.5 W, the reduction in the algal cell density was changed from 37.82 to –52.73% after 7 days of observation period. The gradual decrease in the chlorophyll concentration signified the reduced photosynthetic activity after treatment. The damage created on the cell membrane by ultrasound was evaluated through the increased permeability of electrolytes from the cells and the rise in the conductivity of water. Following the lab-scale experimental studies and interpretation of the results obtained, field trials were carried out at a local natural pond (40*35 sq. metre) for 6 months and secondary clarifier in a local industry (20 m diameter) for 2 months, with some system working based on low power ultrasonic transmitters (power ∼ 25 W/h and frequency 20–40 kHz) and promising improvement in water quality could be observed with 85% and more than 95% algae removal efficiency, respectively.

Design of the System of an Assemblable Channel Slope Weeder

If the grass roots of the water conveyance channel slope dig into the soil, it may cause the soil structure to loosen, and then increase the risk of slope landslide. The operation of manual cleaning weeds is dangerous due to the large slope of the channel. In this context, the design of a channel slope weeder that can adapt to different slopes is very important for the protection of the water channel slope. The weeder concept vehicle designed in this paper is mainly composed of four parts: drive car, frame mechanism, track mechanism and weeder mechanism. At the same time, the structure is analyzed by finite element method, and the stability and safety are analyzed by strength. The reference is provided for the design of the algal removal vehicle on the channel slope.

Improving Microcystis aeruginosa removal efficiency through enhanced sonosensitivity of nitrogen-doped nanodiamonds

Traditional methods for algae removal in drinking water treatment, such as coagulation and sedimentation, face challenges due to the negative charge on algae cells’ surfaces, resulting in ineffective removal. Ultrasonic cavitation has shown promise in enhancing coagulation performance by disrupting extracellular polymer structures and improving cyanobacteria removal through various mechanisms like shear force and free radical reactions. However, the short lifespan and limited mass transfer distance of free radicals in conventional ultrasonic treatment lead to high energy consumption, limiting widespread application. To overcome these limitations and enhance energy efficiency, advanced carbon-based materials were developed and tested. Nitrogen-doped functional groups on nanodiamond surfaces were found to boost sonosensitivity by increasing the production of reactive oxygen species at the sonosensitizer-water interface. Utilizing low-power ultrasound (0.12 W/mL) in combination with N-ND treatment for 5 min, removal rates of Microcystis aeruginosa cells in water exceeded 90 %, with enhanced removal of algal organic matters and microcystins in water. Visualization through confocal microscopy highlighted the role of positively charged nitrogen-doped nanodiamonds in aggregating algae cells. The synergy between cell capturing and catalysis of N-ND indicates that efficient mass transfer of free radicals from the sonosensitizer’s surface to the microalgae’s surface is critical for promoting cyanobacteria floc formation. This study underscores the potential of employing a low-intensity ultrasound and N-ND system in effectively improving algae removal in water treatment processes.

Modification of polyvinylidene fluoride membrane with ciprofloxacin to improve the bacteriostatic performance

The common polyvinylidene fluoride (PVDF) membrane itself is susceptible to membrane fouling, especially biofouling, which is a serious threat. In this study, PVDF membrane was modified with ciprofloxacin (CIP) through co-blending to investigate the filtration properties, bacterial inhibition and fouling resistance. Modified membranes were prepared by adding 0.3 g (MC0.3), 0.6 g (MC0.6), 0.9 g (MC0.9) and 1.2 g (MC1.2) CIP per 100 g casting solution. Among these modified membranes, MC0.6 showed the best filtration performances, with the pure water flux stabilized at about 416.67 L/(m2·h) and bovine serum albumin (BSA) rejection of 92.0% at a trans-membrane pressure of 0.1 MPa. The pore size was reduced, the average roughness was reduced to 29.4 nm, the contact angle was lowered to 68.9°, and the hydrophilicity was greatly improved. The width of the inhibition circle produced by MC0.6 was 0.35–0.45 mm, and the modified membrane showed good inhibition of non-specific bacteria and algal removal during urban river water filtration. The rejection of BSA was increased by 16.32% compared to the base membrane and the adsorption rate for BSA was reduced by 68.45%. In addition, the removal of conventional pollutants in urban river water by the modified membranes for was also improved. Compared with that of the base membrane, the removal of TN, NH3–N, TP and COD by MC0.6 was increased by 10.58%, 12.45%, 15.44% and 13.53%. The results showed that CIP co-blending modified PVDF membrane could effectively improve membrane performances and has good value for water treatment.

Enhanced Coagulation for Algae Removal Using Composite Al-Based Coagulants: Collaborative Optimization Mechanism of Aluminum Morphology

The main purpose of this paper was to reveal the effect of aluminum (Al)-based coagulants on enhanced coagulation for the removal of algae and the synergistic optimization mechanism among different Al species. The formation, breakage, and regrowth processes of algal coagulation flocs formed by a series of monomeric Al-based coagulants (Al2(SO4)3, Al13, and Al30), Al13/Al30 composite coagulant and poly(diallyldimethylammonium chloride)/Al13 (PDADMAC/Al13) composite coagulant were studied. Results indicated that Al13 mainly employed a charge neutralization mechanism, which was conducive to the destabilization of algae and the regeneration of flocs, while Al30 mainly employed a sweep flocculation mechanism, which was conducive to the formation of algae and the strength of flocs. Meanwhile, the charge neutralization was the main mechanism during the algae coagulation process because it could effectively remove the soluble microbial products (SMP) component in the extracellular organic matter (EOM). Therefore, Al13 could achieve a higher coagulation performance than other monomeric Al-based coagulants. The Al13/Al30 composite coagulant could make up for the deficiency of the sweep flocculation mechanism in Al13 and charge neutralization mechanism in Al30, and achieve the best synergistic optimization performance at Al13:Al30-7:3. Additionally, PDADMAC, as a polymer, could further enhance the charge neutralization ability of Al13 at low dosages and the sweep flocculation ability of Al13 at high dosages, respectively. However, an excessive dosage would lead to charge reversal and thus reduce the coagulation effect. Therefore, controlling the dosage was key when using Al-composite coagulants. The findings of our research could offer a certain theoretical foundation for the development of inorganic polymer flocculants.

Scatalysis: Exploring the mechanism of photocatalytic algal removal

Photocatalytic algal removal is an environmentally friendly and low-cost algal bloom control technology. In this work, carbon nitride nanosheets based on morphology control were synthesized, and a ternary Z-scheme photocatalyst was designed through heterojunction engineering for photocatalytic removal of harmful algae and their organic matter, and the removal rate of chlorophyll a was close to 100 % in 300 min. Three-dimensional fluorescence spectrograms and cellular SEM maps revealed the removal of algae and their organic matter, and the mechanism of Ag/AgCl/ZIF-8/SCN photocatalytic algal removal was explored in conjunction with the changes in membrane permeability and various physiological functions. Mechanistic studies showed that excess O2·− played a crucial role in cell inactivation and organic matter degradation. Oxidative stress caused by O2·− promoted the accumulation of H2O2 in cells and accelerates cell death. This study provides new ideas and support for the application of harmful algal bloom control and the mechanism of algal cell inactivation in real water bodies.

Development of PCL/PMMA and PCL/PEG Polymeric Film as Potential for Algae Removal

Human activities generate excess nutrients that can lead to harmful algal blooms (HABs), which are increasing in number and severity worldwide, causing significant ecological problems and substantial economic losses. Cost-effective polymeric films with ease of operation represent a promising and sustainable alternative to traditional HABs mitigation methods in various aquatic systems. In this study, composite polymer films, specifically polycaprolactone with poly(methyl methacrylate) (PCL/PMMA) and polycaprolactone with polyethylene glycol (PCL/PEG), were employed for algae mitigation. To the best of our knowledge, no prior studies have explored the application of PCL/PMMA and PCL/PEG composite polymer films for algae mitigation. These films were prepared using solvent casting methods. The successfully prepared film ratios were 1:0.2, 1:0.4, and 1:0.6. ATR-FTIR analysis confirmed the successful preparation of PCL/PMMA and PCL/PEG by detecting characteristic functional group peaks corresponding to each pure polymer, suggesting the possibility of non-covalent bond interactions between the polymers in the composites. Thermal analysis (TGA) indicated increased thermal stability for all film ratios. Algae mitigation studies form light microscope analysis showed the presence of algal cells within the composite. Removal efficiency improved with higher ratios of these composite polymer films, with PCL/PMMA outperforming PCL/PEG. Notably, the 1:0.4 PCL/PMMA film exhibited highly efficient algae removal, with interactions between microalgae cells and the film observed within a shorter time. This film achieved the highest removal efficiency of 10.6% within a 15-min interval compared to others. From this preliminary study, the composite polymer films show good potential and promising candidate for mitigating algae-related issues.