EFFECT electrolytic dialysis [12] methods have been developed. Nevertheless,

EFFECT OF BLOCKINGAGENT ON BIOSORPTION OF Cu2+, Pb2+, Zn2+ ANDCd2+ FROM AQUEOUS SOLUTION BY SHELL OF KELENGKENG FRUIT (Euphoria logan Lour.

)DesyKurniawati 2)*, Intan Lestari 3), Hermansyah Aziz 1),Zulkarnain Chaidir 1), Rahmiana Zein 1)ABSTRACTThe effect of blocking agent on metals sorption has beeninvestigated. The functional groupscarboxyl and carbonyl modified with blocking agent (methanol 99 % and glycol)in order to determine biosorption capacity of kelengkeng shell (Euphoria longan Lour) of Cu2+,Pb2+, Zn2+ and Cd2+ ions. The chemical blockedwas invesitigated by using Fourier Transform Infrared (FTIR). Determination ofthe possible reduction in metal uptake with the blocking of biosorbent wasperformed in column method. The resultsrevealed inblocking of carboxyl and carbonyl groups decreased of biosorption capacities ofheavy metals by Kelengkeng shellis 36.86 %- 38.

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19 %, approximately. This proved the factthat carboxyl and carbonyl groups in Kelengkengsheels played the main role on biosorption process of heavy metals.Keywords:Biosorption, Column method, Kelengkeng (Euphoria logan Lour) shell, Blockingagent.  INTRODUCTIONImportant environmentalproblems caused by heavy metal pollution due to its toxic effects on theenvironment and accumulation throughout the food chain. The main sources ofheavy metal pollution are the mining industry, milling and surface finishing,the use of various toxic metals such as Cu, Pb, Zn, and Cd into the environment1-3. Heavy metal including cadmium, zinc, copper, and lead as sources ofanthrophogeny, mining, metal plating and other industries waste which are themost common pollutants become an environmental problem of worldwide focus. Allsorts of methods including chemical precipitation orcoagulation 4, 5, 6, ion exchange 7 or adsorption 8–10, membraneseparation 11, and electrolytic dialysis 12 methods have been developed.

Nevertheless,the productiveness of the physical-chemical processes particularly the costeffectiveness are edged. Hence, the low-cost alternative of research is morelikely needed of world wide 4, 13. Nowadays, naturalmaterials and agricultural waste which are subjected by various low-costadsorbents have been proposed as an alternative to remove heavy metal ions fromaqueous solutions 14–16. Some biowaste of agriculture have been proved aseffective toxic heavy metals or dyes removal for instance Garcinia mangostana L. Fruit shell 4, Arenga pinnata Merr fruit shell 8, persimmonpeel 17, tomato waste 18, durian (Duriozibethinus) 19, langsat fruit (Lansiumdomesticum Corr) seed 20, water melon shell 21, lengkeng shell and seed22, 25, etc. Most of biowaste of agriculture have been focused bythe researchers who are interested in the development of biosorbent with muchmore selective and larger capacity in removing metal ions.Biosorptionprocess in values ionic interactions, polar interaction and the combinedinteraction between metal with biopolymers (macromolecules), as the sourcefunctional group, which plays an important role in binding metal ion. Thefunctional group is available at macromolecules such as carboxyl group, amine,hydroxyl, thiolate, phosphodiester, carbonyl and phosphate groups 23.

Inthis study, kelengkeng (Euphoria longan Lour) shell which was an agriculturalproduct waste was used as a biosorbent to removal Cu2+, Pb2+,Zn2+ and Cd2+ ions in water. The shell of kelengkeng wascharacterized by FTIR spectroscopy to identity functional groups in themolecules kelengkeng shell before and after modified with blocking agent. Thisobjective determined the role of carboxyl and carbonyl functional groups inshell of kelengkeng on biosorption of Cu2+, Pb2+, Zn2+and Cd2+  ions.

The research wasdetermined effect of blocking agent in the in functional groups to sorption capacitywith column method. MATERIALS AND METHODSChemical and ApparatusAll materials used inthis research included in an analytical reagent level. Deionized doubledestilled water was performed in the experimental studies. The main solutionwas prepared by Pb(NO3)2 , ZnCl2 , CuSO4,Cd(NO3)2 (1000 mg/L) E-merck,  HNO3 65 %,  NNO3 1 % (v/v), metanol 99 %,etanadiol (glycol), HCl pro analysis. The following apparatus was used: Colomnglass size (1 id x 15) cm, Atomic Absorption Spectrophotometer (AAS, varianAA240, America), FTIR (Perkin elmer, Frountier)Preparation of biosorbentShell of kelengkeng wasused as a biosorbent for biosorption of Cu2+, Pb2+, Zn2+and Cd2+  ions from an aqueoussolution. Shell of kelengkeng was found from the market of Padang city, WestSumatera, Indonesia. Kelengkeng were washed with deionized water, air-dried for7 days and grounded using crusher with particle size 106-425µm.

Blocking Biosobenttreatment proceduresMethanoltreatment: The carboxyl groupwas blocked with blocking agent such as methanol. Blocking process wasperformed by shaking at room temperature, 8 g of the raw biosorbent in 100, 150and 200 mL of 99,9% methanol and concentrated hydrochloric acid (HCl). HCl 0.1M was produced for six hour and 200 rpm and then, the biosorbent was washed byusing deionized water, followed by the air-drying. The dried biosorbent wasready to be used.Glycoltreatment: The carboxyl group of the biosorbent was blockedwith glycol blocking agent. Blocking was carried out by shaking, at roomtemperature, 8 g of the raw biosorbent in 25, 50 and 75 mL of glycol (etanadiol)and concentrated hydrochloric acid (HCl), given a final acidic concentration of0.1 M HCl for 6 h at 200 rpm.

Then the biosorbent was thoroughly washed withdeionized water and then air-dried. The biosorbent was dried and ready to used.ColumnSorption ExperimentsThe column sorptionexperiments were experimented in a 1 cm (internal diameter) and 15 cm (length)of glass column.

In a column process, each blocking and unblocking biosorbentwas entered 0.5 g into the glass column, the standard solution was carried outat pH 3 for sorption of Zn, Pb, Cu ions and Ph 5 for Cd ion in a glass column.Atomic Absoprtion Spectrophotometer (AAS) was used to measure the concentrationof metals of the filtrate. To determine the amount of metals adsorbed byKelengkeng shell, the formula used is:Q= Where:Q is the metal uptake(mg/g), V is volume of solution (L), C0 and Ce is initialand final concentration of metal in solution (mg/ L), M is mass of biosorbent(g).RESULTSAND DISCUSSIONEffectof blocking with methanol solutionColumn biosorption methodwas subjected before and after blocking biomaterial.

It was addressed tocompare the efficiency of biosorption and then the active compoundscontribution existing in biomaterial 24. Thedistribution of metal removal by raw of biomass and blocked biomass aredescribed in Fig. 1.The biosorbent blockingwith methanol had a significant impact on heavy metals removal and determinedthe surface change of carboxyl group in biosorbent.Fig.1 showed the blockingwith 100, 150, and 200 mL methanol 99.

9%, as blocking agent group carboxyl cause a decrease in absorption capacity.The optimization volume for blocking is taken at a volume of 150 mL for Pb2+and Cu2+ and for metals Cd2+  and Zn2+ were taken on a volumeof  200 mL, as in this volume give aminimum uptake from 4.905to 1.792 mg/g for Pb2+, 7.

513to 5.051 mg/g for Cu2+, 2.544 to 2.0 mg/g for Zn2+ and 4.64 to 3,955 mg/g for Cd2+ .Figure1. Effect of the volume blocking agent for  carboxyl groups to biosorption capacity of Cu2+,Pb2+and Cd2+  400mg/L, respectively,  Zn2+ 200mg/L, by kelengkeng shell; particle size 250 mm,mass 0.

5 g, flow rate 2 mL/min. Increasingthe volume of the next methanol relative longer affect the absorption capacityof kelengkeng shell. The decline in kelengkeng shell absorption is apparentlydue esterification reaction of carboxyl to ester cause a reduction in thenumber of active centers negatively changed surface of the kelengkeng shell. Thepurpose of this study were determination of optimum conditions in biosorptionand function of carboxyl groups in the process of biosorption metal cations.

Effectof blocking carbonyl with glycol solutionEffectof the volume of glycol (1,2 ethanediol) of biosorption characteristic to heavymetals sorption by kelengkeng shell shown in Fig. 2.Figure2. Effect of the volume blocking agent for carbonyl functional group tobiosorption capacity of Cu2+, Pb2+and Cd2+ 400mg/L, respectively,  Zn2+ 200mg/L, by kelengkeng shell; particle size 250 mm,mass 0.5 g, flow rate 2 mL/min.Theabsorption capacity for kelengkeng shell unblock on biosorption Pb2+cation about 4.

905mg/g, and 1.6396mg/g after kelengkeng shell treated with 50 ml glycol as blocked carbonylgroups. The results shows that, the carbonyl group in kelengkeng shell plays alarge the biosorption process metal cations.Analysisof Fourier Transform Infrared (FTIR)FTIR which is one ofimportant anlytical techniques detects the characteristic of vibration infunctional groups existing on the surface of adsorbent. Moreover, it describespossible functional group and binding mechanism related to the interactionbetween metal ions 10, 20. The FTIR spectra of kelengkeng shell, after andbefore blocking with methanol and glycol are shown in Fig. 3 (c)   (a)   (b)     Figure 3: FTIR spectra ofkelengkeng shell before blocking (a), Glycol blocking (b), and Methanolblocking (c).

The FTIR spectrum ofbiobsorbent was confirmed by a broad peak at 3422 cm-1. It indicatesthe existence of macromolecular association (cellulose and pectin),  the presence of carbonyl and OH groups 24.The stretching vibration of hydroxyl group is shown a large range offrequencies as the confirmation of the exixtence hydroxyl bond in carboxylicacid group. Symmetric and asymmetric CH stretching vibration of aliphatic acidwas indicated in the band at 2924 cm-1. Symmetric stretchingvibration of CH2 due to CH bonds of aliphatic acids was indicated atpeak 2854 cm-1. The peak of cellulose confirmed as finger printregion at 1000-1200 cm-1. The carboxyl groups band is shown at 1647cm-1 and 1736 cm-1.

The functional group of –COO- inpectin was confrimed at 1373 cm-1.The similar structures ofblocking biosorbent and unblocking biosorbent was confrimed by the similarspectral profile. Nevertheless, by zooming in the spectra, some differenceswere more like to be clearly identified.The modification ofcarboxyl groups with the blocking treatment was confirmed by FTIR spectra. Thedifference between bonding energy related to the modification of carboxyl andcarbonyl groups in cellulose chains was identified as shift in wavenumber at1636 cm-1. CONCLUSIONThelow-cost biosorbent, particularly kelengkel shell with capacity 7.513 mg/g,showed the good performence for the absorption of heavy metals. Ion of Cu2+,Pb2+, Zn2+ and Cd2+ sorption by kelengkengshell blocking was higher compared to blocked methanol of kelengkeng shell whichdecrease from 4.

905 to 1.79 mg/g Pb2+, 7.513 to 5.

051 mg/g Cu2+,2.544 to 2.0 mg/g Zn2+, and 4.64 to 3.95 mg/g Cd2+.Moreover, the metal ions sorption by using blocked glycol of kelengkeng shellare namely decrease from 4.

905 to 1.6396 mg/g Pb2+, 7.513 to 4.885mg/g Cu2+, 2.544 to 1.9604 mg/g Zn2+, and 4.

64 to 3.854mg/g Cd2+. Based on the research result, carboxyl and carbonyl groupin Kelengkeng shell play an important role in the process of biosorption Cu2+,Pb2+, Zn2+ and Cd2+. So, theblocking agent decreases the adsorption capacity of Kelengkeng shell.  ACKNOWLEDGEMENT The special thank isgiven to Directorate General of Higher Education, Ministry of Education andCulture of the Replubic of Indonesia for giving financial support of thisresearch stated in the letter assignment number: 492/UN35.2/PG/2017.