Tris(2-chloroethyl) phosphate (TCEP) has been detected all over the world as a typical refractory organic phosphate, especially in groundwater. This work applied a calcium-rich biochar derived from shrimp shell as a low-cost adsorbent for TCEP removal. Based on the kinetics and isotherm studies, the adsorption of TCEP on biochar was monolayer adsorbed on a uniform surface, with SS1000 (the biochar was prepared at the carbonization temperature of 1000 °C) achieving the maximum adsorption capacity of 264.11 mg·g^-1. The prepared biochar demonstrated stable TCEP removal ability throughout a wide pH range, in the presence of co-existing anions, and in diverse water bodies. A rapid removal rate of TCEP was observed during the adsorption process. When the dosage of SS1000 was 0.2 g·L^-1, 95% of TCEP could be removed within the first 30 min. The mechanism analysis indicated that the calcium species and basic functional groups on the SS1000 surface were highly involved in the TCEP adsorption process.

Algal blooms caused by Microcystis aeruginosa are a common occurrence and pose significant threats to freshwater ecosystems. This study investigates the antialgal effects and underlying mechanisms of two plant-derived fatty acids, nonanoic acid and palmitic acid, on Microcystis aeruginosa. The results show that the inhibitory effects of both fatty acids on M. aeruginosa increase with higher concentrations. Algal recovery occurs when nonanoic acid concentrations are below 0.5 mg/L and palmitic acid concentrations are below 50 mg/L. Acute toxicity tests indicate that the safe concentrations of nonanoic acid and palmitic acid are below 1.87 mg/L and 263.3 mg/L, respectively. The inhibitory effect of nonanoic acid is more pronounced under conditions of pH 5.5, 15 °C temperature, 0.75 mg/L nitrogen, and 2 mg/L phosphorus, with inhibition efficiency remaining unaffected by increased light intensity. Both fatty acids exert their strongest inhibitory effects in the early stages of addition (0–8 days), causing cell death and the release of extracellular organic matter primarily consisting of aromatic compounds and proteins. Oxidative stress analysis reveals that high concentrations of fatty acids can cause irreversible damage to the algae’s antioxidant defense system. These findings provide valuable insights for the prevention and control of cyanobacterial blooms, which can help promote the sustainable development of freshwater ecosystems.

Low concentrations of ammonium are difficult to remove from surface water through traditional adsorption, air stripping, and biological techniques. Hence, we flocculate attapulgite-graft-polyacrylamide (ATP-g-PAM) and immobilize cells in this study to purify low-ammonia surface water. ATP-g-PAM was synthesized by grafting the polymerization reaction of ATP and acrylamide (AM). In this process, FeSO₄ and NaHSO₃ acted as initiators. The optimum reaction conditions were as follows: 15% AM monomer, 2% ATP, 10.5 × 10⁻⁴ mol/mol AM initiator concentration with a 1:5 molar ratio of FeSO₄ to NaHSO₃, and 5 h reaction time. The ATP-g-PAM structure was characterized further by Fourier transform infrared spectra, thermogravimetric analysis, scanning electron microscopy, and transmission electron microscopy. Results indicated that AM monomers were successfully grafted onto the ATP surface. Pellets of ATP-g-PAM-bound nitrifying bacteria were manufactured for surface water treatment. The ammonia-nitrogen removal rate ranged from 14.9 to 33.9% for adsorption and flocculation, and from 69.4 to 82.6% under cell immobilization. Post-treatment, ammonia-nitrogen was less than 0.8 mg/L. Therefore, ATP-g-PAM can be an ideal carrier material of microbial fixations in water and wastewater treatment because the double-action of adsorption and flocculation induced by ATP-g-PAM can supplement the removal of pollutants.

Lake Taihu, China’s third-largest freshwater lake, faces severe eutrophication challenges and therefore requires innovative ecological restoration strategies. This study systematically evaluates the ecological effects of aquatic vegetation restoration in Baimao Bay through comprehensive analysis of macrobenthic communities and environmental parameters, demonstrating significant water quality improvements including a 42.9% decrease in total phosphorus, a 69.4% decline in chl-a concentration, a 34.8% reduction in ammonium nitrogen, and a 81.2% increase in water transparency. Multivariate analysis revealed a fundamental ecological driver shift where post-restoration pH and transparency replaced nutrients as dominant factors, reducing total nitrogen/total phosphorus influence by 40–60%, while filter-feeding species (predominantly bivalves and gastropods) became the dominant macrobenthic biomass group (72.4%) with pollution-tolerant oligochaetes decreasing by 69.1% in abundance, alongside distinct spatial heterogeneity showing pH-regulated lakeshore communities (8.37 to 8.45), transparency-governed shallow-water communities (H′ = 1.35), and a residual nutrient-influenced deep-water area, with a shallow-water area (64 cm) and chlorophyll-a levels (<10 μg/L) for effective eutrophication reversal.