Search Results (6)

Based on the characteristics and effective components of steel slag and desulfurization gypsum, a new type of permeable reactive material was prepared by combining steel slag and desulfurization gypsum, and a simulation experiment of arsenic- and antimony-contaminated groundwater remediation was carried out. A combination of X-ray fluorescent, BGRIMM Process Mineralogy Analyzing System (BPMA), ICP-MS, and SEM-EDS detection and analysis methods was used to investigate the effects of steel slag particle size, desulfurization gypsum particle size, steel slag and desulfurization gypsum ratio, and steel slag-desulfurization gypsum mixed test block particle size on the performance of the permeable reactive wall to remove arsenic and antimony. The results show that a permeable reactive wall composed of steel slag (−4.75 + 1.18 mm) and desulfurization gypsum (−13.2 + 9.5 mm) in a 4:1 ratio achieved removal rates of 91.85% for As and 90.58% for Sb, reducing their concentrations below the drinking water standard. The purpose of using steel slag and desulfurization gypsum to intercept heavy metals and toxic ions in surface runoff was achieved. Arsenic was adsorbed, physically encapsulated, and lattice solidified by C-S-H gel. This research provides a cost-effective and environmentally friendly solution for the storage of steel slag and desulfurization gypsum while addressing heavy metal pollution in groundwater. Full article

Electrochemical technology presents a promising approach for phosphorus recovery from wastewater. Nevertheless, its application in industry is hindered by relatively low phosphorus recovery efficiency, high energy consumption and complex reactor configurations. In this study, a coupled electrolysis and microfiltration system was designed for phosphorus recovery in the shape of iron phosphate compounds with the use of steel pickling wastewater as the iron source. In the electrolysis unit, the anode diffusion layer was extracted from the porous anode surface with the production of an acid effluent and an alkaline effluent. The alkaline effluent was mixed with the stainless steel acid washing wastewater generated from the steel pickling process and then introduced into the microfiltration unit to intercept the iron phosphate crystals. The filtered effluent was finally introduced into the air aeration unit to further reduce the phosphorus content in the water. And the extracted acid solution could be reused in the pickling step of the iron and steel manufacturing process. The experimental results show that the coupled system achieved phosphorus recovery of 42~80% at a current density of 5~20 mA cm⁻², accompanying energy consumption of 5.78~9.15 kWh (kg P)⁻¹ and current efficiency of 79~43%, when the phosphorus concentration was 3 mM and the iron–phosphorus molar ratio was 1.5. After the microfiltration treatment, the residual phosphorus could be further reduced to 0.5 mg L⁻¹ within 30 min at an aeration rate of 80 mL min⁻¹, which met the discharge standard. The presence of interfering ions (HCO₃⁻ and SiO₄²⁻) posed inhibited effects on phosphorus recovery. Generally, this study provides a green and environmentally friendly way to efficiently recover phosphorus resources from wastewater. Full article

Nanofiltration application for the separation of Mg²⁺-Li⁺ from salt-lake brines was attempted in the present work. Four different nanofiltration membranes identified in the manuscript as DL, DK, NF-270, and NF-90 were used to treat salt brine with a magnesium to lithium ratio (MLR) of 61, additionally contaminated by the other ions such as Na⁺, K⁺, Ca²⁺, etc. The effect of the dilution factor, operating pressure, circulation rate, and feed pH were assessed to identify the optimal operating conditions for each membrane based on the retention efficiency of each ion. The results showed an insignificant effect of Ca²⁺ on the retention performance of Mg²⁺-Li⁺. Na⁺ and K⁺ had a smaller hydration radius and larger diffusion coefficient, which competed with Li⁺ and altered the separation of Mg²⁺-Li⁺. Under the optimal conditions (dilution factor: 40; operating pressure: 1.2 MPa; circulation flow rate: 500 L/h; pH: 7), the retention efficiency of lithium was as low as 5.17%, separation factor (SF) was as low as 0.074, and the MLR in the permeate reduced to 0.088. Full article

In this study, by adding zirconium anhydride (ZrO₂) particles to a solution of N–methylmorphorphine–N–oxide (NMMO) and bamboo cellulose (BC), we used interfacial polymerization (IP) to obtain regenerated cellulose nanofiltration membranes (IP–ZrO₂/BC–NFMs) that exhibited high water flow and rejection of salts and dyes. During interfacial polymerization, anhydrous piperazine (PIP) was used as the waterborne monomer, and 1,3,5–trimesoyl chloride (TMC) and n–hexane were used as the organic phase. The procedure was adjusted by analyzing the impacts of the concentrations of the water and organic phase monomers and the reaction duration on the performance of the developed IP–ZrO₂/BC–NFMs. The chemical structures and morphologies of the as–obtained IP–ZrO₂/BC–NFMs were examined using various characterization techniques. The performance of these membranes for removal of inorganic salts and dyes as well as their water flow were investigated. IP–ZrO₂/BC–NFMs obtained at a pressure of 0.5 MPa, PIP concentration of 1.5 wt.%, TMC concentration of 0.15 wt.%, and polymerization period of 2 min displayed the highest water flux (55.12 LMH) and the best desalination effect (NaCl rejection rate = 19.15%). Over 90% of both Methyl Blue (MB) and Congo Red (CR) dyes were intercepted. We demonstrated that the addition of ZrO₂ to nanofiltration membranes significantly enhanced the water flow of the IP–ZrO₂/BC–NFMs as well as the salt ion rejection rate. Full article

ZrO₂ is an excellent ceramic preparation material that can maintain chemical stability in medium–strong acid and alkali environments. The sintering impregnation method was used to prepare the ZrO₂/TiO₂/Al₂O₃ composite nanofiltration membrane (ZTA membrane). Nano-ZrO₂, submicron TiO₂, and microporous Al₂O₃ were used as the surface layer, the transition layer, and the support layer, respectively. The structure and phase of the membrane were measured by scanning electron microscopy (SEM) and X-ray diffractometer (XRD). The composite membrane’s retention, hydrophilic and hydrophobic properties were characterized and evaluated using a UV–Vis spectrophotometer, a water contact angle tester (WCA), and a dead-end filtration device. With the increase in separation layer deposition time, the retention rate of methyl blue increased, and the water flux decreased. At a deposition time of 75 min, the retention rate of methyl blue was more than 80%, and the water flux reached 337.5 L·m⁻² h⁻¹ bar⁻¹ at −1 bar transmembrane pressure. The membranes are hydrophilic and have different interception abilities for metal ions, and the order of retention effect is Ag⁺ > Cu²⁺ > Mg²⁺ > Na⁺, and Ag⁺ and Cu²⁺ reached 65.3% and 50.5%, respectively. The prepared ZTA composite nanofiltration membrane has potential application value in heavy metal ion filtration. Full article

Pyrethroids exposure has been associated with adverse reproductive outcome. However, there is no study that explores the effect of environmental exposure and embryological outcomes. This question was addressed in a prospective cohort of couples undergoing fertility treatment. The study aims to assess the association between urinary metabolites of synthetic pyrethroids and embryological outcomes (MII oocyte count, top quality embryo, fertilization and implantation rate). We included 450 women aged 25–45 undergoing assisted reproductive technology (ART) cycle at Infertility Clinic in Poland. Urine samples were collected at the time of fertility procedure(s) to assess four urinary synthetic pyrethroids concentrations (3-phenoxybenzoic acid (3PBA), cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (cis-DCCA), trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (trans-DCCA), cis-2,2-dibromovinyl-2,2-dimethylocyclopropane-1-carboxylic acid (DBCA)) using validated gas chromatography ion-tap mass spectrometry and calculated for each cycle-specific metabolite. To evaluate the effect of environmental exposure to synthetic pyrethroids and embryological outcomes (methaphase II (MII) oocyte yield, top quality embryo, fertilization rate, implantation rate), multivariable generalized linear mixed analyses with random intercepts were prepared. Urinary 3-PBA concentrations decrease MII oocyte count (p = 0.007) in the fourth quartile (>75 percentile) compared to women in the first quartile (≤25 percentile). Additionally, when 3-PBA was treated as continuous variable, the negative association between exposure to pyrethroids and MII oocyte count was also observed (p = 0.012). Exposure to other pyrethroid metabolities (CDCCA, TDCCA, DBCA) was not related to any of the examined embryological outcomes. Exposure to synthetic pyrethroids may be associated with poorer embryological outcome among couples seeking fertility treatments. As this is the first study on this topic, the results need to be confirmed in further studies. Full article