dragon fruit

Hindawi Publishing CorporationJournal of ChemistryVolume 2013, Article ID 230860, 7 pageshttp://dx.doi.org/10.1155/2013/230860

Research ArticleDragon Fruit Foliage Plant-Based Coagulant forTreatment of Concentrated Latex Euent: Comparison ofTreatment with Ferric Sulfate

Juferi Idris,1 AyubMd Som,2 MohibahMusa,2 Ku Halim KuHamid,2Radah Husen,3 andMiradatul NajwaMuhd Rodhi2

1 Faculty of Chemical Engineering, Universiti Teknologi MARA, Sarawak Campus, 94300 Kota Samarahan, Sarawak, Malaysia2 Faculty of Chemical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Sarawak, Malaysia3 Faculty of Applied Sciences, Universiti Teknologi MARA, Sarawak Campus, 94300 Kota Samarahan, Sarawak, Malaysia

Correspondence should be addressed to Juferi Idris; [email protected]

Received 24 May 2012; Revised 13 September 2012; Accepted 13 September 2012

Academic Editor: Darren Sun

Copyright 2013 Juferi Idris et al. is is an open access article distributed under the Creative Commons Attribution License,which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

e eectiveness of dragon fruit foliage as a natural coagulant for treatment of concentrated latex euent was investigated andcompared with ferric sulfate, a chemical coagulant. Dragon fruit is a round and oen red-colored fruit with scales-like texture and isnative to south American countries which is also cultivated and heavilymarketed in southeast Asian countries. Its foliage representsa part of its overall plant system. Latex euent is one of the main byproduct from rubber processing factories in Malaysia. reemain parameters investigated were chemical oxygen demand (COD), suspended solids (SS), and turbidity of euent. Coagulationexperiments using jar test were performed with a occulation system where the eects of latex euent pH as well as coagulationdosage on coagulation eectiveness were examined. e highest recorded COD, SS, and turbidity removal percentages for foliagewere observed for euent pH 10 at 94.7, 88.9, and 99.7%, respectively. It is concluded that the foliage showed tremendous potentialas a natural coagulant for water treatment purposes. e foliage could be used in the pretreatment stage of Malaysian latex euentprior to secondary treatment.

1. Introductione Malaysian natural rubber industry has become amongthemost important agriculture-based industries in this coun-try. Currently, Malaysia is the third largest natural rubber(NR) producer in the world [1] with total productions ofnatural rubber in 2011 of 996,210 tonnes for both dry andlatex amounted to almost RM 13,278 million [2]. Malaysiarubber industrys contribution to national exports fromnatural rubber, rubber products, hevea wood products, andother rubber in 2011 amounted RM40.42 billion equivalentto 5.82% of Malaysias export [3]. Meanwhile, world rub-ber production and consumption in 2011 were 26,089,000tonnes and 25,850,000 tonnes, respectively [4]. However, theeuents generated from this industry create a major impacton the natural environment. It is estimated that in average,20 tonnes of rubber and 410 thousand litres of euent per

day are produced by rubber factory and some reported 80million litres of untreated rubber euent are discharged dailyinto streams and rivers from the rubber processing factoriesin Malaysia [1, 57]. Untreated latex concentrate euentcomprises a large quantity of water for washing and cleaningof raw materials, small amount of uncoagulated latex, andserum (protein, carbohydrate, lipid, carotenoids, and salt) [1].Highly contaminated with serum contributed to high BOD(Table 1), therefore this euent when discharged into watercourse will deplete dissolved oxygen present in the water andeventually aect aquatic life.

Biological treatments such as pond technology andaerobic and anaerobic methods are the most commonlyused treatment systems. However, these treatment systemscome with large area requirement, high maintenance, longretention time, and high emission hydrogen sulde (H2S)which causes malodour problems associated with treatment

2 Journal of Chemistry

T 1: e characteristics of concentrated latex euent [1, 513] and regulatory discharge standard limits [14].

Parameters Concentrated latexeuent (mg/L)Regulatory standard discharge limit (mg/L)

A BpH 3.75.5 6.09.0 5.59.0Biochemical oxygen demand (BOD) 15007000 20 50Chemical oxygen demand (COD) 350014000 50 100Total solid (TS) 7576 Suspended solid (SS) 200700 50 100Total nitrogen 2001800 Sulfate 5002000 All values except for pH are expressed in mg/L.

of concentrated latex euent using pond systems [1]. It isof high time to identify the best coagulant for coagulationprocesses in order to ensure the nal discharge is well-treated.

Coagulation is an important process in the treatmentof both surface water and industrial wastewater. Its appli-cation includes removal of dissolved chemical species andturbidity via addition of chemical-based coagulants such asalum (AlCl3), ferric chloride (FeCl3), and polyaluminiumchloride (PAC). While the eectiveness of these chemi-cals as coagulants are well-established [15, 16], there are,nonetheless, disadvantages associated with the usage of thesecoagulants such as relatively high procurement costs as wellas detrimental eects on human health and environment.It is therefore desirable that these chemical coagulants arereplaced with cost-eective natural coagulants to counteractthe aforementioned disadvantages.

To date, a variety of natural substances such as bone shellextracts, bark resins, and natural mineral soils have beenexamined for their coagulation properties [17]. Researchon natural coagulants from plant-based material has beenfocused onMoringa oleifera [1821] for the past two decadesbutmore researchers are studying application of other naturalplant coagulants such as cactus Latifaria and Opuntia. It isreported that cactus Latifaria has the potential for use as anatural water treatment coagulant [22] while cactus Opuntiaexhibits high turbidity removal eciency for sewage and sea-water treatment [23]. Opuntia spp. operates predominantlythrough a bridging coagulation mechanism and representsa part of point-of-use water treatment technology for pro-ducing portable water in developing communities [24]. Arecent study indicates that Opuntia cusinica grows in aridand semiarid regions ofMexico and other countries producesmucilage that contains polygalacturonic acid (biopolymer)with interesting coagulating-occulating capabilities with65% of the initial COD being removed at pH 10 (dose of50mg/L) [25].

According to Pichler et al. [26],mucilage derived from thespecies Opuntia cusinica demonstrated high eciency ofthe cactus to eliminate turbidity compared to aluminium sul-fate (Al2(SO4)3). e mucilage extract increased particulate-settling rates 330% compared with aluminium sulfate, atdosage concentration of 3mg/L, while its performance wasequivalent at doses 0.3% of the requiredAl2(SO4)3 concentra-tion. Hence, the positive outcome of studies on cactus-based

wastewater coagulation justies further research on othernatural coagulants.

Coming from the family Cactaceae, dragon fruit ofHylocereus genus or also known as pitaya is a round, juicy,and highly nutritious fruit. It is oen red-colored with scales-like texture and is native to Mexico, central and southAmerica [27]. It is also cultivated and heavily marketed insoutheast Asian countries where the fruit is highly favorable.It is well established as a new crop in Australia, China,Israel, Malaysia, Nicaragua, Taiwan, and Vietnam [28]. ecommercial production of dragon fruit in Israel, Malaysia,and Taiwan produces 1600027000 kg/ha [29]. e foliageof the plant represents a part of its overall system. It can befound abundantly but of no particular usage. In commercialproduction of the fruits, proper foliage thinning is importantin achieving a good fruit size and yield [30].

Wehypothesized that dragon fruit foliage can also be usedfor a similar purpose as cactus Latifaria and Opuntia. In ouropinion, usage of natural coagulant directly contributes tothe global sustainable technology initiatives since the dragonfruit plant is relatively abundant, innocuous, and biodegrad-able. On the basis of the above discussion, the main objectiveof this study is to investigate the eectiveness of dragon fruitfoliage as a natural coagulant for treatment of concentratedlatex euent. Latex euent is one of the main byproductsfrom rubber processing factories in Malaysia which com-prises mainly of carbonaceous organic materials, nitrogen,and sulfate [31].e threemain parameters investigated werechemical oxygen demand (COD), suspended solids (SS), andturbidity of euent. e coagulation eectiveness of thefoliage is compared with ferric sulfate, a chemical coagulant.

2. ExperimentalSamples of concentrated latex euent were obtained fromMARDEX Industrial Latex in Perak, Malaysia. e euentwas collected from the process line prior to chemical oc-culation and sedimentation unit operations within the plant.e samples collection and storing were based on standardmethod for the examination of water and wastewater [32].pH value and temperature of latex euent were determinedusing a portable pHmeter (HACHmodel). Raw concentratedlatex euent is a white-colored suspension at average pH of7.3 and mainly consists of water.

Journal of Chemistry 3

2.1. Preparation of Dragon Fruit Foliage. Dragon fruit foliagewas collected from Tanjung Malim smallholder in Perak,Malaysia. Its thorns were removed and the foliage wassubsequently washed, cut, and dried at 80C. It was blendedinto ne powder and sieved to a particle size range of0.451.25mm.

2.2. Preparation of Ferric Sulfate. Ferric sulfate was pur-chased from chemical company in Subang, Malaysia, inpowder form with approximately 97% purity. Ferric sulfatesolution was prepared by 51.5 g ferric sulfate dissolved in1000mL, 5% (v/v) distilled water solution. e solution waswell stirred for jas test analysis.

2.3. Coagulation Jar Test Experiments. Coagulation exper-iments using jar test were performed in laboratory witha Bioblock occulation that comprises six-paddle rotor(24.5mm 63.5mm) for 500mL high shaped beakers whichis in accordance to standards [32] and all testswere conductedat room temperature. e Jar test coagulation experimentusing dragon fruit foliage and ferric sulfate was conductedseparately. 500mL of latex concentrate euent was pouredinto each of the 6 beakers. e desired amount of coagulantwas added to the suspension and stirred at rapid mixing(120 rpm) for 1 minute. e mixing time and speed wererecorded. e speed of stirrer was reduced to slow mixing(30 rpm) for 20 minutes to keep ocs particles uniformlysuspended. e paddles were then withdrawn and settlingof ocs particles was observed and recorded. e mixturewas le for 1 hour and then the supernatant was collected tobe used in the determination of the COD, SS, and turbidityusing the standard method. e eect of pH was studied inthe range of 211 and the eect of dosage was studied in therange from 200mg/L to 800mg/L. All analyses were done intriplicates and pH of wastewater samples was controlled byadding 1.0M H2SO4 or 1.0M NaOH.

2.4. Analytical Analysis. Turbidity test was performed usingHACH Model 2100P portable turbidimeter with measure-ment in nephelometric turbidity unit (NTU). is tur-bidimeter can measure turbidity from 0.001 to 1000NTUin automatic range mode with automatic decimal point. emeasurement is based on the light-transmitting propertiesof water. Suspended solid was carried out with the aid ofvacuum ltration apparatus. e initial weight of lter paperwas recorded aer drying in the oven at 100C105C for 1hour. A 10mL of the water sample was ltered through aglass bre lter. e residue was dried to constant weight at100C105C for 1 hour. e lter paper was then cooled indessicator before weighing.e total suspended solid contentwas calculated by using equation below:

Suspended Solid

106, (1)

where is weight of disk + remaining solids (g), is weightof empty disk (g), and is volume of sample (mL).

e COD test was performed according to HACH reac-tor digestion procedure, colorimetric determination method

8000 using DR 2000 HACH spectrophotometer with theCOD range from 200 to 15,000mg/L. Since the COD valueof latex concentrated euent was more than 1000mg/L,high range (HR) COD digestion reagent was used withthe concentrated latex euent sample. Two COD digestionreagents were used for both the sample and the blank test.eCOD reactor was rst preheated at 150C followed by placing2 mL of wastewater sample into the vials using volumetricpipettes and deionized water was used to replaced wastewatersample for blank test. e mixtures were mixed and thenplaced in the preheated COD reactor for 2 hours.e reactorwas then turned o and le idle for about 20 minutes priorto cooling to 120C or less. Colorimetric determination wasthen read at 435 COD HR modes.

e BOD experiment was carried out using respirometricmethod (HACH method 10099). It was measured at 20Cunder 5-day incubation. e 20C wastewater sample of aknown range and volume was poured into a BOD tracksample bottle. BOD nutrient buer pillow was added foroptimum bacteria growth. Lithium hydroxide powder pillowwas also added and stirred.e bottle was placed at the BODtrack apparatus inside the incubator at temperature of 20C.e BOD results were taken aer 5-day incubation.

e value of sulfate was performed using DR 2400spectrophotometer. 10mL of treated wastewater was addedinto the sample cell while deionized water was used forreference. SulfateVer 4 reagent powder pillowwas also added,stirred, and then le for 5 minutes for reaction to take place.

e value of ammonia-nitrogen was determined usingDR 2400 spectrophotometer. 0.1mL of treated wastewaterwas added into ammonia-nitrogen reagent while deionizedwater was used for reference. Ammonia salicylate reagentpowder pillow and ammonia cyanurate reagent powderpillow were added into each vial and mixed thoroughly. Bothvials were le for 20 minutes for the reaction to take place.

Carbon (C), Hydrogen (H), and Nitrogen (N) contentsin dragon fruit foliage were determined using the CHNS/OAnalyzer (LECO CHNS932, USA). Approximately 2000mgof very ne cut of oven dried dragon fruit foliage were placedin a tin capsule and crimped.ree types of crimped capsuleswere analyzed; placed in the auto sampler for the CHNS/Oanalyzer Sulfamethazine, and dragon fruit foliage sample andblank as standard. e temperature of the analyzer oxidationwas set at 1000C. A program run the analysis automaticallyand the results were given in percentage.

Malvern Zetasizer 3000 was used to measure zeta poten-tial of dragon fruit foliage coagulant. Experiments were per-formed at coagulant dosage of 0.01mol/L as Fe and pH of thecoagulant solutions was adjusted by adding HCL (1mol/L)or NaOH (1mol/L). Aer 5 minutes of gentle stirring, thesamples were analyzed and the data were recorded.

3. Results and Discussion3.1. Characteristics of Raw Concentrated Latex Euent.Table 2 shows the characteristics of concentrated latex eu-ent before the coagulation pretreatment. e values werewithin the range based on previous result [1, 513] except for


T 2: Values of selected parameters of raw concentrated latexeuent.

Parameters Raw concentratedlatex euentpH 7.3Biochemical oxygen demand (BOD5)at 20C 1527mg/L

Chemical oxygen demand 7857mg/LSuspended solids 1208mg/LSulfate 1290mg/LAmmoniacal nitrogen 101mg/LTurbidity 7243NTU

pH and SS. is was due to the large amount of water usedin factory operation and this can be shown by the pH ataverage of 7.3 during sampling. It is obvious that treatmentof the euent is required before it can be discharged intothe environment since the COD concentration alone ismore than 70 times higher than discharge limit. Furtheranalysis indicated that the BOD/COD ratio is approximately0.17 implying low biodegradability and diculty for naturalattenuation in the environment.

3.2. Characterization of Dragon Fruit Foliage. Elementalanalysis (Table 3) was conducted to provide a comparisonbetween the elemental compositions of the foliage and thatof other natural coagulants, Moringa oleifera, and cactusOpuntia. In this study, it was determined that the foliagecontained 43.1% C, 3.8% N, and 2.9%H.

To investigate the reason of high eciency and the latexconcentrate treatment mechanism of dragon fruit foliagecoagulant, the variation of zeta potential hydrolysis productsas a function of pH was measured. In this series of experi-ments, the pH value was varied by addition of HCL or NaOHsolution. It needs to be pointed out that the pH values in zetaexperiments were the same as the pH of coagulant solution(0.5 g/L). In this study, the working solution was the distilledwater. e data obtained were summarized in Figure 1. Zetapotential is a controlling parameter of charge neutralizationof coagulant and can usually be used to interpret the trendof coagulation eciency. e zeta potential of dragon fruitfoliage coagulant decreased from 32.2 to 15.8mV as the pHwas increased from 4.5 to 7.5. e value of the zeta potentialis practically constant in wide range of pH (from 4 to 8). elatex concentrate in water has a negative charge on its surface,so the higher the positive charge on the coagulant surface, thehigher the latex concentrate removal eciency.

A standard jar test is an important procedure to helpselect the most appropriate coagulant for a particular euenttreatment. It allows individual polymer to be evaluated basedon criteria such as oc formation, settling characteristics,and clarity of treated euent. Figure 2 shows the occulesbefore and aer the coagulation process of concentrated latexeuent using light microscope. Denser and larger occulesclearly appeared aer the coagulation process using dragon

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F 1: Variations of the zeta potential with respect to pH fordragon fruit foliage coagulant.

fruit foliage. is is an early indication of the coagulativecapability of the foliage.

3.3. Eect of Euent pH on Coagulation Eectiveness. pHof the solution during coagulation aects the chemistryof the coagulant. For example, ferric salts undergo rapid,uncontrolled hydrolysis reactions upon their addition towater, forming a series of chemical products or complexes[33]. erefore, it is important to determine the inuenceof controlled latex euent pH on coagulation eectiveness.Figure 3 shows the eect of latex euent pH on coagulationeectiveness at coagulant dosage of 500mg/L. Generally, theCOD, SS, and turbidity removal percentages for ferric sulfateare higher than foliage at corresponding euent pH. ehighest recordedCOD, SS, and turbidity removal percentagesfor foliage were observed for euent pH 10 at 94.7, 88.9, and99.7%, respectively. Ferric sulfate exhibits consistent COD,SS, and turbidity removal within the pH range of 310 inwhich percentage COD removal exceeded 90%.

e curve for foliage is rather dierent compared to ferricsulfate in which there were two discernible peak values atpH 3 and 10 for the former. Nonetheless, it can be argued thatthese two peak values also existed for the ferric sulfate CODcurve albeit, they were not as apparent as the foliage curve.A similar observation is seen from the ndings by Zhanget al. [23] where the lowest turbidity removal percentagesrecorded using cactus Opuntia are at pH 6 and 7 while theoptimum pH is 10. It is interesting to note that this twopeak pH phenomenon is not exclusive to this study (ornatural coagulant) but also observed in other coagulationstudies aswell. Findings fromAziz et al. [34] on color removalfrom landll leachate using ferric sulfate indicate a similartrend in which the two peak pH values are 4 and 12 withlower colour removal percentages at pH 6 and 7. In theirndings, these two peak pH values are far more discerniblecompared to our ferric sulfate study most probably due tochemicals present in latex euent which are more amenableto the formation of ocs and not so much so for chemicals inlandll leachate. e suggest that the relatively lower removalpercentages at euent pH around 7 for foliage as well asobserved in the aforesaid studies are caused by solutionneutrality as opposed to acidic and basic pH where theelevated concentration of either H+ or OH causes moreelectrostatic interactions between the coagulant and chemicalspecies in the euent and thus promotes coagulation.


T 3: Elemental analysis of dragon fruit foliage and comparison with other natural coagulants.

Parameters ShelledMoringa seeds [35] NonshelledMoringa seeds [35] Cactus Opuntia [36] Dragon fruit foliageC (%) 54.8 53.3 29.4 43.1N (%) 6.1 5.0 2.3 3.8H (%) 8.5 7.7 1.7 2.9

(a) (b)

F 2: Floccules (a) before and (b) aer the coagulation process of concentrated latex euent.

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SS (ferric sulfate)Turbidity (ferric sulfate)

F 3: Eect of latex euent pH on coagulation eectiveness atcoagulant dosage 500mg/L.

3.4. Eect of Coagulant Dosage on Coagulation Eectiveness.Figure 4 shows the eect of coagulant dosage on coagulationeectiveness at optimumpHvalues of 10 and 7 for foliage andferric sulphate, respectively. ese pH values were selectedbased on our previous ndings in this study. For ferricsulfate dosage range of 250750mg/L, COD and turbidityremoval percentages showed marginal dierence in whichmore than 98% removal was achieved. Similarly, foliagedosage range of 200800mg/L showed consistent removalof COD and turbidity (>95%). It appeared that SS removalpercentages were consistently lower than that of COD andturbidity for both coagulants. It was rather obvious that bothcoagulants showed high removal percentages (>88%) for allthe investigated parameters even though it could be argued

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F 4: Eect of coagulant dosage on coagulation eectiveness atoptimum euent pH.

that the foliage showed marginally lower COD removalpercentages (>95%) compared to ferric sulfate (>99%). euse of natural coagulants may increase the organic load inwaters [37] resulting in the possibility for undesired andincreased microbial activity [24]. As such, this factor maybe partly responsible for the foliage not achieving CODremoval percentage as high as exhibited by ferric sulfate.is is because increased microbial activity increases BODconcentration and subsequently contributes to increasedCOD concentration in an aqueous solution.

3.5. Comparison with Malaysian Standard Euent DischargeLimit. A crucial aspect of industrial wastewater treatmentis to reduce contaminants concentrations of point-source


euent discharge to within regulatory permissible limits. Assuch, it is of interest to evaluate the extend of eectivenessof foliage in reducing the COD and SS concentrations of thelatex euent with respect to regulatory euent dischargelimit, so that suitability of the foliage as a pretreatment or all-inclusive coagulant can be determined.

Figure 5 analyzes the compliance of COD and SS con-centrations of treated latex euent (at optimum pH) withstandard euent discharge limits A and B stipulated by theDOE, Malaysia. Ferric sulfate is capable of reducing both theCOD and SS concentrations to lower than Standard A limit(50mg/L) at a dosage range of 300500mg/L. is indicatesthat the ferric sulfate can be used as an all-inclusive coagulantfor treating Malaysia latex euent produced by a rubberprocessing plant located downstream of a water supply intakepoint, though this aspect is greatly dependent on the initialCOD concentration of the euent (which should be lowerthan 7800mg/L to be applicable).

For foliage, SS concentrations of treated euent uc-tuated around Standard B limit (100mg/L) while its cor-responding COD concentrations were clearly higher thanStandard A and B for all dosages. Nonetheless, it is erroneousto construe from this observation that the foliage is anineective or unsuitable coagulant for latex euent sincethe foliage is capable of removing more than 88% of CODconcentrations as proven in previous sections. erefore, byconsidering the two aspects of removal percentages as well asregulatory compliance, it can be surmised that the foliage canbe used in the pretreatment stage of Malaysian latex euentprior to secondary treatment. From this study, it can beimplied that dragon fruit foliage shows tremendous potentialas natural coagulant for water treatment purposes. CODremoval percentages of more than 88% are rather impressiveas the latex euent contains an amalgamation of organic andinorganic substrates which normally complicate coagulationtreatment.We suggest that the foliagemay even exhibit highercontaminant removal percentages for less complex or soluteconcentrated waters such as surface water (rivers and lakes).

4. ConclusionGenerally, the COD, SS, and turbidity removal percentagesfor ferric sulfate were higher than foliage at correspondingeuent pH. However, this was not a true indication ofthe relative coagulative eectiveness of the foliage. elower removal percentages for foliage were probably due toincreased organic load from biological components of foliageand subsequently contributed to increased BOD and CODconcentrations in the solution media. e highest recordedCOD, SS, and turbidity removal percentages for foliagewere observed for euent pH 10 at 94.7, 88.9, and 99.7%,respectively, which were rather impressive considering thecomplex chemical nature of the latex euent. As such, itcould be concluded that the foliage showed tremendouspotential as natural coagulant for water treatment purposes.For this study, since the foliage showed high COD removalpercentages and yet could not reduce the COD concentra-tions to less than Standard B limit, it is suggested that itcould be used in the pretreatment stage of Malaysian latex

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F 5: Comparison analysis of COD and SS concentrations oftreated latex euent (at optimumpHof 10 for foliage and 7 for ferricsulfate) with standard euent discharge limits A and B stipulated bytheDepartment of the Environment,Malaysia [14]. Initial COD andSS concentrations were 7857 and 1208, respectively.

euent prior to secondary treatment. For future study, it isrecommended that the dragon fruit foliage be used for otherwastewater treatments.

Acknowledgmentse authors gratefully acknowledge the Research Manage-ment Institute (RMI), Universiti Teknologi MARA, for pro-viding research grant for this study, Universiti TeknologiMARA, Sarawak Campus for facilities, and technical supportand management of MARDEX Industrial Latex Sdn Bhd forproviding the latex euent samples.

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