The threat of oil pollution increases with the expansion of oil exploration and production activities, as well as the industrial growth around the world. The study on the treatment of oily wastewater is a critical issue to the environmental protection as oil caused problems to the wastewater treatment facilities. Although oil particles can efficiently be removed by advanced technologies, the treatments are usually expensive and difficult to maintain. Adsorption and coalescence filtration are promising choice of treatment for its simplicity, effectiveness, and feasibility when appropriate sorbent is used. This review discusses the recent papers on the use of natural fibrous sorbent for removal of oil from wastewater, and its current development. With their excellent oil removal properties, environmental friendliness, easy availability, and feasibility, natural fibrous sorbents are an attractive alternative for oily wastewater treatment.

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Palm kernel shell (PKS) core fibers, an agricultural waste, were chemically modified using N(3chloro2hydroxypropyl) trimethylammonium chloride (CHMAC) as a quaternizing agent. The potential of quaternized palm kernel shell (QPKS) as an adsorbent for fluoride in an aqueous solution was then studied. The quaternized palm kernel shell (QPKS) core fibers were characterized using Fourier transform infrared spectroscopy (FTIR) and a scanning electron microscope (SEM). The effect of various factors on the fluoride sequestration was also investigated. The results showed that with an increase in the adsorbent amount and contact time, the efficiency of fluoride removal was improved. The maximum fluoride uptake was obtained at pH 3 and a contact time of 4 h. The adsorption behavior was further investigated using equilibrium isotherms and kinetics studies. The results from these studies fit well into Freundlich, RedlichPeterson, and Sips isotherm's with a coefficient of determination (R2) of 0.9716. The maximum fluoride removal was 63%. For kinetics studies, the pseudo second order was the best fit for fluoride, with an R2 of 0.999. These results suggest that QPKS has the potential to serve as a lowcost adsorbent for fluoride removal from aqueous solutions.

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With oil and grease content of 4000-8000 mg/l in palm oil mill effluent (POME), the commonly used ponding system often fails to produce treated effluent that meets the minimum standard of treated effluent. The present study investigates the efficiency of sago bark (SB) and esterified sago bark (ESB) for removal of emulsified oil from POME. Oil removal experiments were conducted at different batch experimental conditions: namely adsorbent dosage, contact time, temperature and pH. In overall, the oil removal efficiency of both SB and ESB increased with the increasing of sorbent dosage and contact time. 24-h oil adsorption test afforded oil removal efficiency of 57.77% (SB) and 80.23% (ESB).On the other hand, the oil removal efficiency of both SB and ESB decreased with the increasing temperature. Acidic pH was favorable pH condition for high oil removal efficiency in POME. There was a good correlation (R2 > 9.5) between experimental data and the intra-particle diffusion model for both SB and ESB. The adsorption of oil in POME using SB was best described by Freundlich isotherm (R2 = 0.998), indicating heterolayer adsorption of oil on SB. The adsorption of oil in POME using ESB was better represented using Langmuir isotherm (R2 = 0.992), indicating a monolayer adsorption of oil onto the ESB surface. In conclusion, ESB showed better potential for use as sorbent for removing emulsified oil from wastewater, particularly POME.

Deposition behavior of spray dried full cream milk, skim milk and whey particles were observed in a pilot scale dryer. Particle surface dominated with fats exhibit gradual decrease in deposition fluxes when transition from the initial adhesion to the subsequent cohesion mechanism. Whey protein, however, displayed significant differences in the adhesion and cohesion fluxes. Reduction of particle deposition on low energy chamber wall surface is more significant for the hydrophobic whey particles. Further analysis shows that the reduction in droplet-wall contact energy is larger for the more hydrophobic droplet, delineating weaker adhesion interaction. The results suggest that the hydrophobicity of the depositing particles in an important consideration when using lower chamber wall with lower surface energy. This is in addition to the effect of particle rigidity and deposition strength as reported previously.

This paper investigates the ability of activated carbon derived from waste newspaper (WNAC) to remove pesticide glyphosate from aqueous solution. The influence of initial pH was first studied. It was found that the WNAC presented the highest uptake capacity at pH 2.5. Adsorption isotherm models such as Langmuir, Freundlich and Redlich-Peterson were used to describe the adsorption of glyphosate by WNAC. The results show that the Langmuir adsorption isotherm model best fits the experimental data. The maximum adsorption capacity of WNAC is found to be 48.4 mg/g.

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. Esterification is one of the widely used chemical modifications to increase oil removal efficiency of natural fibres [14,[17][18][19][20]. Many esterification studies on natural fibres via acetylation in the presence of acetic anhydride have been conducted [21]. The hydroxyl (-OH) group in rice, wheat, rye, barley straws, and poplar wood fibre has been successfully replaced with acetyl groups via acetylation [19] Acetylation of sugarcane bagasse with Nbromosuccinimide (NBS) as the catalyst affords oil sorption capacity of 13.5-20.2 g/g on machine oil [20]. Acetylated banana fibre gives high oil sorption capacity (18.12 g/g) for machine oil [18]. Acetylated cotton [2] and acetylated wheat straw [14] show the reduction of the -OH group and the appearance of the three ester bands associated with successful acetylation at 1740-1745 cm À1 (C5 5O stretching of ester), 1369 cm À1 (C-H in -O(C5 5O)-CH 3 ), and 1234 cm À1 (C-O stretching of acetyl group attributed to C5 5O). However, the drawback in using acetic anhydride is the formation of acetic acid as by-product. Acetic acid causes residual smell, loss in material strength due to acidic hydrolysis of holocelullose, and metal fastener corrosion [21]. An interesting alternative in esterification of natural fibres is using fatty acid derivatives with water as a by-product [17]. Banerjee et al. studied on the esterification of sawdust using oleic acid, stearic acid, and decanoic acid in hexane with H 2 SO 4 as the catalyst, at 65 8C Sago or Metroxylon sagu, harvested in Sarawak, Malaysia, is a low-cost, natural adsorbent. The sago bark (SB) from M. sagu was investigated for adsorptive removal of emulsified oil in palm oil mill effluent (POME). Hydrophobicity of this sorbent in aqueous state was improved via esterification process. The esterification of SB was conducted at ratio of sago bark to stearic acid (SA) by 1:1, 4:1, and 7:1; percentage catalyst of 5, 10, and 15; and refluxing time 1, 4.5, and 8 h; respectively. These parameters were analysed using full central composite design (CCD) of response surface methodology (RSM). The adjusted R-squared value of 0.9509 showed that the regression model fit the data well. The predicted Rsquared value (0.9168) also indicated that the prediction of experimental data was satisfactory. Hydrophobicity test, FTIR, and SEM were carried out to characterise the esterified sago bark (ESB). Results showed that esterification process successfully increased the hydrophobicity of sago bark by 42.2% and oil removal efficiency in POME by 50.2%. A developed two-factor interaction (2FI) model showed that the preparation conditions of 1:1 SB:SA, 1...