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This study explores the silicon dioxide nanoparticles (SiO2) green production via employing Eucalyptus globulus leaf extract and potassium metasilicate. Characterization methods, including FTIR, dynamic light scattering, SEM, Brunauer‒Emmett‒Teller analysis, and XRD. All these approaches were applied to get an in-depth comprehension of the nanoparticle's properties. It was determined that the nanoparticles' average size was 127 nm and 218 m2g–1 surface area. In addition, the tests verified the SiO2 nanoparticles' purity and demonstrated the surface existence of many reactive groups. The effectiveness of the reactive SiO2 nanoparticle groups were then assessed in a batch-mode adsorption under various operating parameters for the removal of malachite green dyes from aqueous solutions. The investigation examined the contact duration, pH, temperature, agitation speed, starting dye concentration, and quantity of nanomaterial on adsorption effectiveness. Experimental results demonstrated a remarkable removal efficiency of 96% for malachite green dye at an initial concentration of 100 ppm in the contaminated solution. Interestingly, the percentage removal exhibited an inverse relationship with dye concentration and temperature, while being directly proportional to other factors. Overall, the green-synthesized silicon dioxide nanoparticles proved to be a promising adsorbent for the effective removal of malachite green dye from aqueous environments. The results highlight the potential application of these nanoparticles in wastewater treatment and pollution mitigation, offering a sustainable and eco-friendly solution for environmental challenges. [ABSTRACT FROM AUTHOR]

Sawdust, as an agricultural waste which is highly efficient, readily available, and relatively inexpensive, has the potential to be an applicable alternative adsorbent for the total organic carbon (TOC) removal from synthetic domestic wastewater. This study aims firstly to investigate the feasibility of sawdust as a new adsorbent and understand its adsorption mechanism for TOC. The impact of particle size, pH, contact time, and temperature has been evaluated as the controlling factors on the adsorption process. The results presented that the removal efficiency rose with the decrease of particle size, pH, and temperature, as well as the increase of the contact time. The maximum adsorption was obtained at particle size of 0.05 mm, pH of 1, contact time of 1.5 h, and temperature of 15oC, respectively. The second aim of this study is to utilize the sawdust that is used in the adsorption process as biomass in batch anaerobic digestion (AD) to produce methane. Spent sawdust was characterized by the methane production which was 5.9 times greater than in the case of raw sawdust. Four operating parameters were checked, Carbon/Nitrogen ratio (C/N), inoculation, particle size, and total solid (TS) content. The batch results indicated that the optimum parameters were: 20%, 30%, 2 mm, and 15%, respectively. [ABSTRACT FROM AUTHOR]

Wastewater containing antibiotics can pose a significant threat to biological wastewater treatment processes. This study investigated the establishment and stable operation of enhanced biological phosphorus removal (EBPR) by aerobic granular sludge (AGS) under mixed stress conditions induced by tetracycline (TC), sulfamethoxazole (SMX), ofloxacin (OFL), and roxithromycin (ROX). The results show that the AGS system was efficient in removing TP (98.0%), COD (96.1%), and NH 4 +-N (99.6%). The average removal efficiencies of the four antibiotics were 79.17% (TC), 70.86% (SMX), 25.73% (OFL), and 88.93% (ROX), respectively. The microorganisms in the AGS system secreted more polysaccharides, which contributed to the reactor's tolerance to antibiotics and facilitated granulation by enhancing the production of protein, particularly loosely bound protein. Illumina MiSeq sequencing revealed that putative phosphate accumulating organisms (PAOs)-related genera (Pseudomonas and Flavobacterium) were enormously beneficial to the mature AGS for TP removal. Based on the analysis of extracellular polymeric substances, extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, and microbial community, a three-stage granulation mechanism was proposed including adaption to the stress environment, formation of early aggregates and maturation of PAOs enriched microbial granules. Overall, the study demonstrated the stability of EBPR-AGS under mixed antibiotics pressure, providing insight into the granulation mechanism and the potential use of AGS for wastewater treatment containing antibiotics. [Display omitted] • EBPR was achieved with AGS in municipal wastewater containing mixed antibiotics. • LB-PN had an increasing positive effect on the granulation. • XDLVO theory provided a good explanation for the microbial aggregation process. • The granulation mechanisms of EBPR-AGS under antibiotics pressure was proposed. • Pseudomonas and Flavobacterium were beneficial to the mature AGS for TP removal. [ABSTRACT FROM AUTHOR]