Removal of micropollutants from municipal wastewater using different types of activated carbons.

The water reservoirs are getting polluted due to increasing amounts of micropollutants such as pharmaceuticals, organic polymers and suspended solids. Powdered activated carbon (PAC) has been proved to be a promising solution for the purification of water without having harmful impacts on the environment. Parameters such as PAC dosing, wastewater hardness, the effect of coagulant and flocculant were evaluated in a batch scale study. These parameters were further applied on a pilot plant scale for the performance evaluation of PAC based removal of micropollutants concerning the contact time and PAC dosing with main focus on recirculation of PAC sludge. The obtained optimum dose was 10-20 mg/L providing 84.40-91.30% removal efficiency of suspended solid micropollutants (MPs) and this efficiency increased to 88.90-93.00% along with coagulant which further raised by the addition of polymer and recirculation process at batch scale. On pilot plant scale, the concentration in contact reactor and PAC removal effectiveness of dissolved air flotation, lamella separator and sedimentation tank were compared. Constant optimisation resulted in a concentration ranging from 2.70 to 3.40 g/L at dosing of PAC 10 mg/L, coagulant 2.00 mg/L and polymer 0.50 mg/L. PAC doses of 10-20 mg/L with 15-30 min contact time proved best for above 70-80% elimination. The recirculation system has also proved an efficient technique because the PAC's adsorption capacity was practically completely used. Small PAC dosages yielded high micropollutants elimination.

Kinetic and equilibrium study of graphene and copper oxides modified nanocomposites for metal ions adsorption from binary metal aqueous solution.

Presently, the main cause of pollution of natural water resources is heavy metal ions. The removal of metal ions such as nickel (Ni2+) and cadmium (Cd2+) has been given considerable attention due to their health and environmental risks. In this regard, for wastewater treatment containing heavy metal ions, graphene oxide (GO) nanocomposites with metal oxide nanoparticles (NPs) attained significant importance. In this study, graphene oxide stacked with copper oxide nanocomposites (GO/CuO-NCs) were synthesized and characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and atomic force microscopy (AFM) analytical procedures. The prepared GO/CuO-NCs were applied for the removal of Ni2+ and Cd2+ ions from a binary metal ion system in batch and continuous experiments. The obtained results revealed that GO/CuO-NCs exhibited the highest removal efficiencies of Ni2+ (89.60% ± 2.12%) and Cd2+ (97.10% ± 1.91%) at the optimum values of pH: 8, dose: 0.25 g, contact time: 60 min, and at 50 ppm initial metal ion concentration in a batch study. However, 4 mL/min flow rate, 50 ppm initial concentration, and 2 cm bed height were proved to be the suitable conditions for metal ion adsorption in the column study. The kinetic adsorption data exhibited the best fitting with the pseudo-second-order model. The adsorption isotherm provided the best-fitting data in the Langmuir isotherm model. This study suggested that the GO/CuO nanocomposites have proved to be efficient adsorbents for Ni2+ and Cd2+ ions from a binary metal system.

Is Antifibrinolytic Therapy Effective for Preventing Hemorrhage in Patients with Hemophilia Undergoing Dental Extractions? A Systematic Review and Meta-Analysis.

OBJECTIVES: This systematic review aims to analyze the systemic administration of antifibrinolytics (tranexamic acid and aminocaproic acid) to prevent postoperative bleeding in patients with hemophilia. METHODS: This systematic review was conducted adhering to PRISMA guidelines. Only randomized controlled trials that assessed human subjects of any age or gender with any severity of hemophilia undergoing dental extractions, and systemically administered antifibrinolytic therapy compared to placebo were included. Post-operative bleeding episodes and adverse events were presented. PubMed, Cochrane, Embase, CINAHL, Web of Science, and Scopus were searched through April 15, 2022. The risk ratio (RR) and odds ratio (OR) applying 95% confidence intervals (CI) were computed using RevMan 5.4.1 (Cochrane). RESULTS: Two randomized, placebo-controlled trials pooling in a total of 59 patients were pooled in this analysis. Among patients administered antifibrinolytic therapy, 84% reduced risk of post-operative bleeding was reported (RR = 0.16, 95% CI = 0.05-0.47, P = 0.0009). The chances of post-operative bleeding were reduced by 95% among the antifibrotics group (OR = 0.05, 95% CI = 0.01-0.22, P < 0.0001). CONCLUSION: This review finds favorable outcomes for the routine use of antifibrinolytic therapy for dental extractions in hemophiliacs. Further trials are required to rationalize existing evidence.