Fish pond water treatment using ultrasonic cavitation and advanced oxidation processes

Efficient elimination of carbamazepine using polyacrylonitrile-supported pyridine bridged iron phthalocyanine nanofibers by activating peroxymonosulfate in dark condition

The monoaminotrinitro iron phthalocyanine (FeMATNPc) is used to connect with isonicotinic acid (INA) for amide bonding and axial coordination to synthetic a unique catalyst FeMATNPc-INA, which is loaded in polyacrylonitrile (PAN) nanofibers by electrospinning. The introduction of INA destroys the π-π conjugated stack structure in phthalocyanine molecules and exposes more active sites. The FeMATNPc-INA structure is characterized by X-ray photoelectron spectroscopy and UV-visible absorption spectrum, and the FeMATNPc-INA/PAN structure is characterized by Fourier transform infrared spectroscopy and X-ray diffraction. The FeMATNPc-INA/PAN can effectively activate peroxymonosulfate (PMS) to eliminate carbamazepine (CBZ) within 40 minutes (PMS 1.5 mmol/L) in the dark. The effects of catalyst dosage, PMS concentration, pH and inorganic anion on the degradation of CBZ are investigated. It has been confirmed by electron paramagnetic resonance, gas chromatography-mass spectroscopy and free radical capture experiments that the catalytic system is degraded by •OH, SO4•- and Fe (IV) = O are the major active species, the singlet oxygen (1O2) is the secondary active species. The degradation process of CBZ is analyzed by ultra-high performance liquid chromatography-mass spectrometry and the aromatic compounds have been degraded to small molecular acids.

Performance of wetland applied to ecological remediation of abandoned fish ponds: A case study in Gonghu Bay, Tai lake

To restore the abandoned fish ponds to "near natural" state, the wetland restoration was carried out in Gonghu Bay lakeside, and its long-term performance of controlling external load was studied for 5 years. The findings showed that water quality and biodiversity had been improved dramatically after the preliminary transformation. The concentrations of permanganate index (COD_Mn), total nitrogen (TN), and total phosphorus (TP) obviously decreased from 12.91 mg L^-1 to 4.32 mg L^-1, from 3.46 mg L^-1 to 1.42 mg L^-1, and from 0.27 mg L^-1 to 0.04 mg L^-1, respectively. The proportion of Cyanophyta was effectively reduced from 31.82% to 18.89%, and favored the growth of diatoms (31.82%-37.78%) to be the dominant algae species. Aquatic plant species and coverage gradually increased from 16 to 56 and from 5% to 60%, respectively. An in-deep monitoring done for 5 years (2013-2017) showed that the wetland achieved a satisfactory removal efficiency of 58.95% for TN, 64.60% for TP, and up to 77.83% for chlorophyll-a. Besides, three pollution scenarios, such as stormwater runoff, algal bloom, and continuous water transfer, were selected to explore the tolerance of the wetland to the suddenly increased pollution loads. The results dedicated that even if the inlet load was up to 1.0 × 10⁵ m³ d^-1, the removal rate coefficients of wetland for chlorophyll-a, TP, and TN were 0.135-0.239 d^-1, 0.041-0.112 d^-1, and 0.030-0.109 d^-1, respectively, which were equivalent to the well-running wetlands. This study confirmed that the wetland was not only a promising ecological remediation technique to contaminated abandoned fish ponds, but also could withstand high pollution load, which had the prospect of sustainable utilization.

Trends and characteristics of employing cavitation technology for water and wastewater treatment with a focus on hydrodynamic and ultrasonic cavitation over the past two decades: A Scientometric analysis

Cavitation-based technologies have emerged as a sustainable and effective way to treat natural waters and wastewater, considering their increasing scarcity due to pollution and climate change. For this reason, this work aimed to conduct a scientometric analysis on the topic of cavitation for water and wastewater treatment during the last 20 years, from 2001 to August 2022. We focused on hydrodynamic and ultrasonic cavitation as the prevalent methods of inducing cavitation. Furthermore, an in-depth study on the main trends regarding the number of publications and citations, keywords co-occurrence and evolution, and countries' publication trends was carried out to investigate the future direction of this research topic. The data was gathered from the Web of Science database and analyzed by the Visualization Of Similarities software. This work focused on: i) publication and citation trends, ii) scientific categories, iii) countries' contribution to the topic of cavitation, iv) prominent journals, v) keyword co-occurrence and cluster analysis, and vi) keyword evolution analysis. Results showed a significant increase in publications during the past 5 years. The scientific categories with the highest number of publications were "environmental sciences" and "environmental engineering," with a combined share of 19.4 % of publications. Keywords evolution analysis showed that limited focus was given to topics related to "energy" and "energy efficiency" in the field of cavitation, but with the rising importance of each process's sustainability, the attention given to these concepts will increase in the future. Future directions for the topic of cavitation-related water and wastewater treatments will shift towards more environmentally friendly applications of hydrodynamic and ultrasonic cavitation as well as towards more green and sustainable approaches to address the increasing water pollution problems and shortage. Moreover, it will include other uses besides water treatment such as manufacturing nanomaterials food production and medicine.

Purification of aquaculture effluent using Picralima nitida seeds

Aquaculture effluent treatment is essential to eliminate the undesirable characteristics of water to ensure cleaner production and environmental sustainability. In an effort to develop green coagulant without compromising cost, this research investigated the feasibility of aquaculture effluent (AQEF) pollutant removal using Picralima nitida seeds extract (PNSC) and its bio-coagulation/adsorption kinetic characteristics with the substrate in water. The coagulative decrease was observed in terms of TD (turbidity), TSS (total suspended solids), COD (chemical oxygen demand), BOD (biochemical oxygen demand), and COLR (color) from AQEF. The active coagulant was extracted from the seeds and analyzed for its spectral and morphological characteristics through FTIR and SEM. The influence of PNSC dosage (0.10-0.50 g L^-1), pH (2-10), settling time (0-60 min), and temperature (303-323 K) on the removal of contaminants were surveyed. The process kinetics of coagulation-flocculation were also explored. Maximal TD reduction of 90.35%, COD (82.11%), BOD (82.38%); TSS (88.84%), and COLR (65.77%) at 0.2 g PNSC L^-1, pH 4, and 303 K was achieved. Analysis of variance (ANOVA) tests proved that pH, temperature, and settling time had a significant effect on pollutant removal. Results fitted Von Smoluchowski's perikinetics theory at the optimum conditions, which gave R² > 0.900. At perikinetics circumstances, the K_b (reaction rate) and [Formula: see text] (half-life) correspond to 0.0635 Lg^-1 min^-1 and 1.9 min. More so, sorption results fitted the Lagergren over the Ho model. Additionally, the net cost of using PNSC to handle 1 L of AQEF (including electricity, material, and labor costs) was evaluated to be €4.81. Overall, the PNSC appears reliable and useful in pretreating AQEF for improved biodegradability and superior effluent quality.

Treatment of heavy metals containing wastewater using biodegradable adsorbents: A review of mechanism and future trends

The direct disposal of industrial effluents into the aquatic system is considered as a significant environmental hazard in many countries. Because of poisonous chemicals, substantial volumes of effluent release, as well as the lack of adequate of conventional treatment methodologies, industrial effluent treatment is extremely difficult. Numerous researchers have been interested in adsorption technology for its high efficiency of pollutant removal, low cost, and abundantly available adsorbent. Various adsorbent materials, both natural and modified form, have been widely used for the removal of toxic contaminants from industrial effluent. This paper highlights recent advancements in multiple modification types to functionalize the adsorbent material, resulting in higher adsorption capacity on various toxic pollutants. This review provides an overview of the adsorption mechanism and parameters (pH, adsorbent dosage, initial concentration, temperature and interaction time), which influencing the removal efficiency of adsorbents. Furthermore, this review compiles the desorption study to recover the adsorbent and improve the cycle's financial viability. This review provides a concise overview of the future directions and outlook in the framework of adsorbent application for industrial wastewater treatment.

Acoustic characterization of cavitation intensity: A review

Cavitation intensity is used to describe the activity of cavitation, and several methods are developed to identify the intensity of cavitation. This work aimed to provide an overview and discussion of the several existing characterization methods for cavitation intensity, three acoustic approaches for charactering cavitation were discussed in detail. It was showed that cavitation noise spectrum is too complex and there are some differences and disputes on the characterization of cavitation intensity by cavitation noise. In this review, we recommended a total cavitation noise intensity estimated via the integration of real cavitation noise spectrum over full frequency domain instead of artificially adding inaccurate filtering processing.