Ibuprofen is well known as one of the most frequently detected pharmaceuticals and personal care products (PPCPs) in rivers. However, sorption of ibuprofen onto sediment has not been considered in spite of its high K _ow (3.5). In this study, the effects of various environmental conditions such as pH (4, 5.3, and 7), the concentrations of dissolved organic matters (0 to 1.0 mM citrate and urea), salinity (0, 10, 20, and 30 part per thousand), and presence of other PPCP (salicylic acid) on ibuprofen sorption were investigated. Linear model mainly fitted the experimental data for analysis. The distribution coefficient (K _d) in the linear model decreased from 6.76 at pH 4 to near zero at pH 7, indicating that neutral form of ibuprofen at pH below pKa (5.2) was easily sorbed onto the sediment whereas the sorption of anionic form at pH over pKa was not favorable. To investigate the effect of dissolved organic matters (DOMs) on ibuprofen sorption, citrate and urea were used as DOMs. As citrate concentration increased, the K _d value decreased but urea did not interrupt the ibuprofen sorption. Citrate has three carboxyl functional groups which can attach easily ibuprofen and hinder its sorption onto sediment. Salinity also affected ibuprofen sorption due to decrease of the solubility of ibuprofen as salinity increased. In competitive sorption experiment, the addition of salicylic acid also led to enhance ibuprofen sorption. Conclusively, ibuprofen can be more easily sorbed onto the acidified sediments of river downstream, especially estuaries or near-shore environment with low DOM concentration.

Antibiotic contaminants, which are generally present in bi-solute systems, can be competitively adsorbed onto clays. Single- and bi-solute sorptions of sulfadiazine (SDZ) and ciprofloxacin (CIP) onto montmorillonite and kaolinite were investigated at pH values of 5 and 8. Freundlich and Langmuir models were used and fit the experimental data well for single-solute sorption. The sorption isotherms were nonlinear (N_F = 0.265–0.730), and the maximum sorption capacities (q_mL) of the SDZ and CIP onto montmorillonite were higher than those onto kaolinite. The octanol–water distribution ratio (D_ow), cation exchange capacity (CEC), Brunauer–Emmett–Teller (BET) surface area (A_BET), pore size, point of zero charge (pH_PZC), and basal spacing predominantly affected the Freundlich constant (K_F) and q_mL of SDZ⁰ and CIP⁺ at pH 5 more than SDZ⁻ and CIP^± at pH 8. For bi-solute sorption, the presence of CIP inhibited the SDZ sorption onto montmorillonite and kaolinite. Competitive sorption models such as Sheindorf–Rebhun–Sheintuch (SRS), Murali–Aylmore (M–A) and the modified extended Langmuir model (MELM) were used; of these, the MELM provided the best prediction with SDZ sorption onto montmorillonite at pH 8 and CIP onto kaolinite at pH 5 and 8 in SDZ/CIP system occurring synergistically, whereas others occurred antagonistically. The distribution coefficient (K_d) of the bi-solute sorption decreased with increasing pH in the order cationic > neutral > anionic for SDZ and cationic > zwitterionic > anionic for CIP, which resembled the K_d of single-solute sorption. Fourier transform infrared spectroscopy (FT-IR) spectra indicated that amine in SDZ and keto oxygen in CIP were responsible for the interactions with the montmorillonite and kaolinite. GRAPHICAL ABSTRACT

A combined process consisting of Moving-Bed Biofilm Reactors (MBBRs) with Polyurethane-Dyeing Sludge Carbonaceous Material (PU-DSCM) foam and chemical coagulation was investigated for dyeing wastewater treatment. The pilot-scale MBBR system was composed of two aerobic MBBRs in series. Each reactor was filled with 20% (v/v) of Polyurethane-Dye Sludge Carbonaceous Material foam (PU-DSCM foam) inoculated with a white-rot fungus, Phanerochaete chrysosporium, for biological treatment followed by chemical coagulation with FeCl₂ or alum. In the MBBR process, 79% of COD and 54% of color (influent COD = 539 mg/L and color = 622 PtCo units) were removed at MLSS concentration of 2900 mg/L attached to the PU-DSCM carrier and 48 hr of short Hydraulic Retention Time (HRT) at steady state. The biologically treated dyeing wastewater was subjected to chemical coagulation. After coagulation with alum at the optimum dosage (1.55 mg alum/mg COD), 95.7% of COD and 73.4% of color were removed in overall. The combined process of fungal MBBRs and chemical coagulation has promising potential for dyeing wastewater treatment.

The biosorption of Cd, Co, and Cu onto three microalgae species (Chlorella vulgaris, Scenedesmus sp., and Spirulina platensis) was compared to determine the microalgae’s capability for heavy metal adsorption in acidic and neutral environments. The Langmuir, Freundlich, and Dubinin–Radushkevich isotherm models were used to characterize the adsorption of the heavy metals onto microalgae. The maximum adsorption capacity (q_max) determined using the Langmuir and D-R model showed results in the order of Cu > Co > Cd in both acidic and neutral conditions. A shift from acidic to neutral conditions increased the microalgae’s adsorption affinity for heavy metals, as determined using the Freundlich parameter (K_F). The adsorption affinity of the biomass for Cd and Co was in the order S. platensis > C. vulgaris > Scenedesmus sp. while that of Cu was in the order C. vulgaris > Scenedesmus sp. > S. platensis. In addition, it was found that the adsorption of Cd and Co enhanced the production of Dissolved Organic Content (DOC) as a byproduct of biosorption, whereas the adsorption of Cu appeared to suppress the generation of DOC. The mean adsorption energy (E) values computed by the D-R model were less than 8 (kJ/mol), indicating that physisorption was the primary force of sorption in both acidic and neutral settings. The findings of this study suggest that microalgae may be used as a low-cost adsorbent for metal removal from industrial effluent.

Apart from the conventionally used iron (Fe) and aluminum (Al) electrodes in microalgae harvesting, experiments were designed to examine the viability of lead (Pb), magnesium (Mg), zinc (Zn), and copper (Cu) as electrode materials in the harvesting of microalgae. The effect of voltage on the flocculation efficiency (FE) of the electrode materials was examined and compared. By dividing the optimal FE values by their corresponding periods, a simple yet practical approach was used to rank the electrode materials. From highest to lowest flocculation efficiency, the results were as follows: Cu, Zn, Mg, Al, and Pb at 10 V; Mg, Zn, Cu, Al, and Pb at 20 V; and Mg, Zn, Al, Cu, and Pb at 30 V. Important factors such as temperature, periodic FE, consumption of electrode material, pH, and metallic concentrations in the effluent were evaluated. The temperature increase proposed to have been affected by electric resistance drop and anodic corrosion, between 1.7 °C and 3.3 °C, 5 °C and 8.9 °C, and 10.5 °C and 18.4 °C was recorded at 10 V, 20 V, and 30 V respectively. Except for the supernatants of the experiments from Al electrodes, which remained relatively unaffected by voltage and time, the pH of all the other supernatants increased with time and voltage. The effluents recorded metallic concentrations between 0.513 mg/L and 43.8 mg/L for Pb, 7.02 mg/L and 20.5 mg/L for Mg, 1.34 mg/L and 9.09 mg/L for Al, 0.079 mg/L and 0.089 mg/L for Zn, and 0.252 mg/L and 0.434 mg/L for Cu electrodes.