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Abstract Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic compounds, composed of benzene rings. The objective of this research was to identify the optimum condition for the degradation of PAHs contaminated water using photo-Fenton oxidation process via response surface methodology (RSM). Aqueous solution was prepared and potable water samples were collected from water treatment plants in Perak Tengah, Perak, Malaysia in September 2016. The reaction time, pH, molarity of H 2 O 2 and FeSO 4 were analyzed followed by RSM using aqueous solution. A five level central composite design with quadratic model was used to evaluate the effects and interactions of these parameters. The response variable was the percentage of total organic carbon (TOC) removal. PAHs quantification was done using gas chromatography mass spectrometry analysis. The regression line fitted well with the data with R 2 value of 0.9757. The lack of fit test gives the highest value of Sum of Squares (15,666.64) with probability F value 0.0001 showing significant quadratic model. The optimum conditions were established corresponding to the percentage of TOC removal. The PAHs removal efficiency for potable water samples ranged from 76.4% to 91% following the first order of kinetic rates with R 2 values of >0.95. Conventional water treatment techniques are not effective for PAHs removal. Thus, advanced oxidation processes may be considered as an alternative to conventional water treatment techniques in Malaysia and other developing countries. Graphical abstract Unlabelled Image Highlights • PAHs are carcinogenic compounds and abundantly found in mixed use area. • Perak River serves as principal water intakes in Perak Tengah, Perak, Malaysia. • Conventional water treatment techniques are inefficient for PAHs removal. • This research studies Photo-Fenton Oxidation Process for PAHs removal in water. • AOPs may be considered as an alternative to conventional water treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • The physicochemical properties of hydrogel polymers in diapers were presented. • WDXRF, FTIR, XRD, pH, turbidity and colour were studied. • The chemical composition (chemical oxides) was determined. • The functional groups and chemical contents were identified. • The crystallinity, pH, turbidity and colour of ND and UD were described. Diapers are reusable waste. This research presents physicochemical properties of sodium polyacrylate in new (ND) and used (UD) diapers, via wavelength-dispersive X-ray fluorescence (WDXRF), Fourier transform infrared (FTIR), X-ray diffraction (XRD), pH, turbidity and colour. Additional constituents detected in ND, while others were slightly higher in UD. Slight decrease (2000–2500 cm−1, UD) and bulk peaks (3287–3333 cm−1, UD) were observed and functional group at 2897 cm−1 (ND) disappeared showing their role as absorption sites. The pH (6.83–8.50), turbidity (16.3–36.6 NTU) and colour (153–432 Pt.Co) values were obtained. Thus, this provides a baseline reference for diapers application in concrete technology. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are mutagenic and bio-accumulates in nature. This research aims to determine the ecological and health risk assessment of PAHs in Sungai Perak, Malaysia. The sampling was conducted at the up and downstream of Sungai Perak in the district of Perak Tengah, Malaysia. The sampling stations were Tanjung Belanja Bridge (TBB), Water Treatment Plant Parit (WTPP), Parit Town Discharge (PTD), Water Treatment Plant Senin (WTPS) and Water Treatment Plant Kepayang (WTPK). The water treatment plants channel water through the distribution network, to Manjung (249,600 people), Perak Tengah (249,600 people), Kinta (810,400 people) and Hilir Perak (144,400 people) districts. The hazard quotient (HQ) and hazard index (HI) were applied for ecological and health risk assessments. The lifetime cancer risk (LCR) was employed for the health risk assessment. The PAHs contamination level presumptions for all sampling campaigns were low (0–100 μg/L). The HI values of ecological and health risk assessments were found to be aligned with each other. The HI values for raw water were below one (<1) indicating low or no risk while the treated water HI values were more than one (>1) indicating to high risk to aquatic organisms and human health. However, the LCR for raw and treated water exceeded the maximum permissible limit, 1.0 × 10−6 equals to cancer risk of 1 in 1,000,000 people. The LCR for raw water were 1.71 × 10−4 (TBB), 1.35 × 10−4 (WTPP), 1.43 × 10−4 (PTD), 9.54 × 10−5 (WTPS) and 2.37 × 10−4 (WTPK). Meanwhile, the LCR for treated water were 6.90 × 10−5 (WTPP), 5.42 × 10−5 (WTPS) and 2.63 × 10−4 (WTPK). The conventional water treatment system appears to be inefficient to remove PAHs, risking the security of public health. Thus, restructuring the infrastructure of water treatment plants or considering an alternative to rivers as domestic water sources are highly recommended. [Display omitted] • Ecological and health risk assessments of PAHs in Sungai Perak were presented. • Sungai Perak posed low PAHs contamination level presumptions (0–100 μg/L). • Risk to aquatic organisms and human health: Raw (HI < 1) and treated (HI > 1) water. • The LCR for a population exceeded 1.0 × 10−6. • The conventional water treatment system is inefficient, risking the public health. [ABSTRACT FROM AUTHOR]

[Display omitted] • The physicochemical and leaching properties of FA and BA were presented. • BA and FA shown similar pozzolanic property, potential as alternative binder. • Heavy metals leaching of FA, BA and FA + BA were in permissible limits. • Pb is an indicator for existence of other heavy metals (i.e. Zn, Cu and As) Coal ash (fly (FA) and bottom (BA) ashes) contain heavy metals. This research presents physicochemical and leaching properties of coal ashes (FA, BA and FA + BA) from a Malaysian power plant. The physicochemical (X-ray fluorescence (XRF) and scanning electron microscopy (SEM)) and leaching properties (toxicity characteristic leaching (TCLP) and synthetic precipitation leaching (SPLP) procedures) of ash samples were determined. Heavy metals like lead (Pb), zinc (Zn), copper (Cu) and arsenic (As) were quantified using atomic absorption spectrometer (AAS). Leaching properties were found to complied to the standard guidelines for heavy metals. Further investigation on leaching properties is recommended for construction industry applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Rough set theory and PCA were applied for environmental data modelling. • The similarity assessment of 16 + 1 US EPA PAHs from Sungai Perak is presented. • LMW PAHs were found to be the most prominent in the water. • Variance were equal to 68.47% (Nap) and 27.63% (carbazole) • The LMW PAHs were likely due to incomplete combustion from vehicles. This paper presents application of rough set theory and PCA for modelling of similarity characteristics of PAHs from Perak River: Tanjung Belanja Bridge (TBB, l 1), Water Treatment Plant Parit (WTPP, l 2), Parit Town Discharge (PTD, l 3), Water Treatment Plant Senin (WTPS, l 4), and Water Treatment Plant Kepayang (WTPK, l 5). The clustering involved PAHs as attributes and sampling stations as objects. The l 1 and l 3 were clustered in Sim deg x , y ≥ 0.8. The Sim deg x , y ≥ 0.7 was observed in all attributes (except l 5) forming two sets of clusters. PCA showed that low molecular weight (LMW) PAHs were prominent with variances of 68.47% (naphthalene, Nap) and 27.63% (carbazole). [ABSTRACT FROM AUTHOR]

The water stream has been reported to contain non-steroidal anti-inflammatory drugs (NSAIDs), released from households and premises through discharge from Sewage Treatment Plant (STP). This research identifies commonly consumed NSAIDs namely ibuprofen (IBU), diclofenac (DIC), ketoprofen (KET) and naproxen (NAP) in the influent wastewater from two urban catchments (i.e. 2 STPs). We expand our focus to assess the efficiency of monomer (C18) and dimer (HLB) types of sorbents in the solid phase extraction method followed by gas chromatography mass spectrometry (GCMS) analysis and optimize model prediction of NSAIDs in the influent wastewater using I-Optimal design. The ecological risk assessment of the NSAIDs was evaluated. The HLB produced reliable analysis for all NSAIDs under study (STP1: 6.7 × 10−3 mg L−1 to 2.21 × 10−1 mg L−1, STP2: 1.40 × 10−4 mg L−1 to 9.72 × 10−2 mg L−1). The C18 however, selective to NAP. Based on the Pearson proximity matrices, the DIC HLB can be a good indicator for IBU HLB (0.565), NAP C18 (0.721), NAP HLB (0.566), and KET HLB (0.747). The optimized model prediction for KET and NAP based on DIC are successfully validated. The risk quotients (RQ) values of NSAIDs were classified as high (RQ > 1), medium (RQ, 0.1–1) and low (RQ, 0.01–0.1) risks. The optimized models are beneficial for major NSAIDs (KET and NAP) monitoring in the influent wastewater of urban domestic area. An upgrade on the existing wastewater treatment infrastructure is recommended to counteract current water security situation. [Display omitted] • Influent wastewater of urban domestic area contains NSAIDs. • IBU, NAP, KET and DIC were analysed. • The efficiency of C18 and HLB sorbents were assessed. • The model parameters of NSAIDs in influent wastewater were modelled. • The estimated RQ values of NSAIDs were high, medium, and low risks. [ABSTRACT FROM AUTHOR]