Search

Refractory pollutants like pharmaceuticals and dyes have become excessively prevalent in most Malaysian water bodies because of the growing textile and pharmaceutical industries. Hence, this work employed activated carbon prepared from freely available paper mill sewage sludge for removing chloramphenicol (CAP) and methylene blue (MB). Modest treatment of low-temperature carbonisation assisted with a short activation time of microwave radiation had been used. Analysis of variance of central composite design resulted in the optimum conditions of 440-W radiation power and 3-min activation time for optimum removal of 70% CAP and 51% MB. The surface area of the paper mill sewage sludge activated carbon (PMSSAC) improved greatly from 1.14 to 412 m2/g, with the highest adsorption capacity of 13 mg/g. The scanning electron microscope images demonstrated the efficiency of microwave radiation treatment, where more cavities and pores were observed on activated carbon for improved adsorbate penetration. The Freundlich isotherm and the pseudo-second-order model appeared to best fit the kinetic data. Furthermore, the high affinity of adsorbate towards the PMSSAC surface could be the plausible mechanism, as indicated by the high amount of adsorption within the initial stage of adsorption. Thus, it is envisaged that our PMSSAC could be effectively employed in actual wastewater systems, as evidenced by excellent CAP and MB removal. [ABSTRACT FROM AUTHOR]

This study evaluates the adsorptive capacity of elephant grass (EG) in the removal of Methylene blue (MB) dye from wastewater sourced from two major local dyeing industries in Ogun State, Nigeria. Batch adsorption method was used to determine the optimum conditions, characterization of the adsorbent, equilibrium Isotherm models, kinetics and thermodynamics studies were conducted to evaluate the nature of the adsorption process. The optimum adsorption conditions obtained for the standard solution of MB dye were; pH 7, Temp 40 °C, contact time 180 min and adsorbent dosage 2.0 g. The presence of oxygen containing functional groups and shift or disappearance of bands in the FTIR suggested the suitability of EG for the process. The SEM of EG revealed presence and disappearance of pores before and after the adsorption process. The mechanism of this adsorption is complex, the adsorption data is best fitted to Langmuir isotherm, the mean adsorption energy E (≤6.455 kJ/mol), and activation energy (10.84 kJ/mol) represents physical process but, the thermodynamic studies revealed spontaneity (ΔG° −15.93 to −14.26 kJ mol−1), randomness, and endothermic (ΔH° 40.1 kJ/mol) nature, representing chemisorption. Therefore, local dyers around the study sites can make use of the freely available EG for the remediation of their wastewater. Elephant grass (EG) abundantly thrives on the study sites where dye wastewater is released by local dyers. This serves as the impetus for this research as no other plants thrive on the dye-polluted environment. A favorable adsorption was obtained with EG as adsorbent for the Methylene blue (MB) dye that is a major constituent of the wastewater from the two major local dyeing industries investigated. Therefore, this study provides scientific support for the local dyers around the study sites to make use of the freely available EG for the remediation of their wastewater. [ABSTRACT FROM AUTHOR]

Hydroxyapatite-coated quartz sands were synthesized by the sol–gel method and employed as a permeable reactive barrier (PRB) medium for the manganese contaminated aqueous solution treatment. The effects of composite particle size, initial concentration of manganese, and hydraulic load on the manganese removal in aqueous solution were investigated by column test. The Thomas and Yoon-Nelson dynamic models were used to reproduce the Mn(II) adsorption behavior observed in these column experiments. The scanning electron microscope (SEM) coupled with energy dispersive spectrometer (EDS), X-ray diffractometer (XRD), and X-ray photoelectron spectroscopy (XPS) were employed to investigate the Mn(II) removal mechanism. Results showed that the initial concentration of manganese had the greatest influence on Mn(II) removal when the initial concentration of manganese is 3 mg/L, the particle size is 0.15 ~ 0.3 mm, the hydraulic load is 5.5 m3/m2·d, and the adsorption capacity of the composites reached the maximum of 1.10 mg/g. The Thomas model fitted the breakthrough curves better. The maximum adsorption capacity of Mn(II) is 0.7546 mg/g. The adsorption mechanisms are mainly ion exchange and dissolution–precipitation. The results indicate that the hydroxyapatite-coated quartz sands could be an effective PRB media for the manganese-contaminated water treatment. [ABSTRACT FROM AUTHOR]

The pollution of manganese (Mn) ion in both surface and groundwater occurs naturally or by anthropogenic sources. The high level of Mn(II) causes neurological disorder similar Parkinson's disease. This study reviews the reported manganese removal technique from aqueous solutions, including bioremediation, adsorption, filtration, chemical precipitation, and other techniques such as electrocoagulation, ion exchange, coagulation and flocculation, oxidation and filtration, membrane processes, and using oxidation chemicals presenting available choices to solve the problem of manganese pollution. The bioremediation and adsorption technique were found to be the most practical and mostly accepted in the literature. Based on findings this study, in ground waters the highest level of manganese 4.39 to 62.62 mg/L was found in Chhattisgarh, and the lowest level was 0.00 to 0.11 mg/L found in Nigeria. This review summarizes existing awareness on several perspectives of the principals and utilization of removal technique of manganese and critically reviews the difficulties to its commercial achievement and future aspects. [ABSTRACT FROM AUTHOR]

The pollution of manganese (Mn) ion in both surface and groundwater occurs naturally or by anthropogenic sources. The high level of Mn(II) causes neurological disorder similar Parkinson's disease. This study reviews the reported manganese removal technique from aqueous solutions, including bioremediation, adsorption, filtration, chemical precipitation, and other techniques such as electrocoagulation, ion exchange, coagulation and flocculation, oxidation and filtration, membrane processes, and using oxidation chemicals presenting available choices to solve the problem of manganese pollution. The bioremediation and adsorption technique were found to be the most practical and mostly accepted in the literature. Based on findings this study, in ground waters the highest level of manganese 4.39 to 62.62 mg/L was found in Chhattisgarh, and the lowest level was 0.00 to 0.11 mg/L found in Nigeria. This review summarizes existing awareness on several perspectives of the principals and utilization of removal technique of manganese and critically reviews the difficulties to its commercial achievement and future aspects. [ABSTRACT FROM AUTHOR]

Bisphenol A is a well-known endocrine-disrupting compound that is commonly detected in industrial effluents and wastewater treatment plants. It is extensively used in the production of polycarbonate and epoxy resins. It is linked to serious environmental pollution and negative effects in humans and living microorganisms, i.e., malfunction of the endocrine system through imitating or blocking natural hormones. Several bisphenol A remediation techniques have been investigated over the last decades, with many of them gradually emerging as effective ones. This article summarizes the most recent findings and progress of the highly effective and widely accepted bisphenol A elimination/degradation techniques, such as membrane separation, adsorption, advanced oxidation processes, and biodegradation, based on their beneficial and optimistic aspects, namely, ease of operation, excellent bisphenol A removal performance, and cost-effectiveness. The operational specifications affecting the elimination efficiency and concerning mechanisms of the processes are summarized. The prominent remarks from this article are as follows. (i) Reverse osmosis, membrane distillation, and nanofiltration-based membrane separation processes particularly eliminated ~100% of bisphenol A from the contaminated aqueous solutions; however, the durability and force resistance frame integrity of the membranes need to be increased. Combining the membrane separation techniques with other oxidation/biodegradation techniques can lower the major issues of each technique; i.e., integrating the membrane separation and electrochemical oxidation can reduce the fouling and mass transfer limitation issues of both the techniques, respectively. (ii) Numerous conventional and nonconventional adsorbents can effectively eliminate bisphenol A from effluents; however, the higher adsorbability and rapid adsorption rates need to be addressed. (iii) Mono/bimetal ion-loaded catalysts could significantly degrade bisphenol A via photocatalysis; however, variation in reaction rates, catalyst deactivation owing to fouling, complex structures, intricate fabrication methods, and uncontrollable morphology of metal-based nanocatalysts remain the core issues. (iv) Numerous bacterial species/fungi/fungal enzymes and microalgae can effectively biodegrade bisphenol A with comparatively higher efficiencies. Finally, prominent remarks and perspectives from this paper provide perception and future investigation directions to address existing problems of bisphenol A-contaminated wastewater treatment. [ABSTRACT FROM AUTHOR]

The use of heavy metals in the manufacturing industry over the past few decades has eventually contributed to a rise in the flow of metallic compounds into wastewater and has raised significant ecological and health threats to living things. Adsorption is an excellent way to treat solid waste effluent, offering significant benefits such as affordability, profitability, ease of operation and efficiency. However, the price of commercial adsorbent namely activated carbon has soared due to its high demand. There is also a green improvement in this method by turning the commercial adsorbent into agricultural waste. In Malaysia, the oil palm waste is such suitable material that can be utilized for making activated carbon, since they are ample and easy to find. Additionally, part of them is agricultural waste that cannot be consumed (i.e. leaves and fronds). Hence, this study aimed to analyse the potential of activated carbon from agricultural waste, namely oil palm waste, in reducing the levels of heavy metals in industrial wastewater. [ABSTRACT FROM AUTHOR]